diff --git a/README.md b/README.md
index f2b9e9a1..527e867a 100644
--- a/README.md
+++ b/README.md
@@ -3,6 +3,6 @@
 
 Development occurs in language-specific directories:
 
-|[Haskell](hs) ![Haskell CI](https://github.com/ephemient/aoc2023/workflows/Haskell%20CI/badge.svg)|
-|--:|
-|[Day1.hs](hs/src/Day1.hs)|
+|[Haskell](hs) ![Haskell CI](https://github.com/ephemient/aoc2023/workflows/Haskell%20CI/badge.svg)|[Kotlin](kt)|
+|--:|--:|
+|[Day1.hs](hs/src/Day1.hs)|[Day1.kt](kt/aoc2023-lib/src/commonMain/kotlin/com/github/ephemient/aoc2023/Day1.kt)|
diff --git a/kt/.gitignore b/kt/.gitignore
new file mode 100644
index 00000000..cade4039
--- /dev/null
+++ b/kt/.gitignore
@@ -0,0 +1,5 @@
+.gradle/
+.idea/
+build/
+local.properties
+*~
diff --git a/kt/README.md b/kt/README.md
new file mode 100644
index 00000000..9d655a80
--- /dev/null
+++ b/kt/README.md
@@ -0,0 +1,34 @@
+# [Advent of Code 2023](https://adventofcode.com/2023)
+### my answers in [Kotlin](https://www.kotlinlang.org/)
+
+This project builds with [Gradle](https://gradle.org/).
+
+Run the test suite:
+
+```sh
+./gradlew :aoc2023-lib:allTests
+```
+
+Run [kotlinx.benchmark](https://github.com/Kotlin/kotlinx-benchmark) ([JMH](https://openjdk.java.net/projects/code-tools/jmh/)) benchmarks:
+
+```sh
+./gradlew :aoc2023-exe:benchmark
+```
+
+Print solutions for the inputs provided in local data files:
+
+```sh
+./gradlew :aoc2023-exe:jvmRun :aoc2023-exe:run{Debug,Release}Executable{LinuxX64,Macos{X64,Arm64},MingwX64}
+```
+
+Run all checks, including [Detekt](https://detekt.github.io/) static code analysis and [ktlint](https://ktlint.github.io/) formatter:
+
+```sh
+./gradlew check
+```
+
+Check for newer versions of dependencies:
+
+```sh
+./gradlew :dependencyUpdates
+```
diff --git a/kt/aoc2023-exe/build.gradle.kts b/kt/aoc2023-exe/build.gradle.kts
new file mode 100644
index 00000000..7b1ad9ff
--- /dev/null
+++ b/kt/aoc2023-exe/build.gradle.kts
@@ -0,0 +1,65 @@
+import org.jetbrains.kotlin.gradle.plugin.mpp.KotlinNativeTarget
+import org.jetbrains.kotlin.gradle.targets.jvm.KotlinJvmTarget
+
+plugins {
+    application
+    kotlin("multiplatform")
+    kotlin("plugin.allopen")
+    alias(libs.plugins.kotlinx.benchmark)
+    id("com.github.ephemient.aoc2023.detekt")
+    id("com.github.ephemient.aoc2023.kotlin.multiplatform.jvm.platform")
+    id("com.github.ephemient.aoc2023.kotlin.multiplatform.native.platforms")
+}
+
+application {
+    mainClass = "com.github.ephemient.aoc2023.exe.Main"
+}
+
+kotlin {
+    jvm {
+        withJava()
+    }
+
+    targets.withType<KotlinJvmTarget> {
+        mainRun {
+            mainClass = application.mainClass
+        }
+    }
+
+    targets.withType<KotlinNativeTarget> {
+        binaries.executable {
+            entryPoint = "com.github.ephemient.aoc2023.exe.main"
+        }
+    }
+
+    sourceSets {
+        commonMain {
+            dependencies {
+                implementation(projects.aoc2023Lib)
+                implementation(libs.kotlinx.coroutines)
+            }
+        }
+
+        commonTest {
+            dependencies {
+                implementation(libs.kotlinx.benchmark)
+            }
+        }
+
+        nativeMain {
+            dependencies {
+                implementation(libs.okio)
+            }
+        }
+    }
+}
+
+allOpen {
+    annotation("org.openjdk.jmh.annotations.State")
+}
+
+benchmark {
+    targets {
+        register("jvmTest")
+    }
+}
diff --git a/kt/aoc2023-exe/src/commonMain/kotlin/com/github/ephemient/aoc2023/exe/CommonMain.kt b/kt/aoc2023-exe/src/commonMain/kotlin/com/github/ephemient/aoc2023/exe/CommonMain.kt
new file mode 100644
index 00000000..06f845b6
--- /dev/null
+++ b/kt/aoc2023-exe/src/commonMain/kotlin/com/github/ephemient/aoc2023/exe/CommonMain.kt
@@ -0,0 +1,14 @@
+package com.github.ephemient.aoc2023.exe
+
+import com.github.ephemient.aoc2023.days
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.withContext
+
+internal suspend fun mainImpl(vararg args: String): Unit = withContext(Dispatchers.Default) {
+    for (day in days) {
+        if (args.isNotEmpty() && day.name !in args) continue
+        println("Day ${day.name}")
+        for (part in day.solver(getDayInput(day.day))) println(part())
+        println()
+    }
+}
diff --git a/kt/aoc2023-exe/src/commonMain/kotlin/com/github/ephemient/aoc2023/exe/IO.kt b/kt/aoc2023-exe/src/commonMain/kotlin/com/github/ephemient/aoc2023/exe/IO.kt
new file mode 100644
index 00000000..1a159c15
--- /dev/null
+++ b/kt/aoc2023-exe/src/commonMain/kotlin/com/github/ephemient/aoc2023/exe/IO.kt
@@ -0,0 +1,3 @@
+package com.github.ephemient.aoc2023.exe
+
+internal expect suspend fun getDayInput(day: Int): String
diff --git a/kt/aoc2023-exe/src/commonTest/kotlin/com/github/ephemient/aoc2023/exe/Day1Bench.kt b/kt/aoc2023-exe/src/commonTest/kotlin/com/github/ephemient/aoc2023/exe/Day1Bench.kt
new file mode 100644
index 00000000..4074277e
--- /dev/null
+++ b/kt/aoc2023-exe/src/commonTest/kotlin/com/github/ephemient/aoc2023/exe/Day1Bench.kt
@@ -0,0 +1,26 @@
+package com.github.ephemient.aoc2023.exe
+
+import com.github.ephemient.aoc2023.Day1
+import kotlinx.benchmark.Benchmark
+import kotlinx.benchmark.Scope
+import kotlinx.benchmark.Setup
+import kotlinx.benchmark.State
+import kotlinx.coroutines.runBlocking
+
+@State(Scope.Benchmark)
+class Day1Bench {
+    private lateinit var input: String
+
+    @Setup
+    fun setup() {
+        input = runBlocking {
+            getDayInput(1)
+        }
+    }
+
+    @Benchmark
+    fun part1() = Day1(input).part1()
+
+    @Benchmark
+    fun part2() = Day1(input).part2()
+}
diff --git a/kt/aoc2023-exe/src/jvmMain/kotlin/com/github/ephemient/aoc2023/exe/IO.kt b/kt/aoc2023-exe/src/jvmMain/kotlin/com/github/ephemient/aoc2023/exe/IO.kt
new file mode 100644
index 00000000..9865e508
--- /dev/null
+++ b/kt/aoc2023-exe/src/jvmMain/kotlin/com/github/ephemient/aoc2023/exe/IO.kt
@@ -0,0 +1,10 @@
+package com.github.ephemient.aoc2023.exe
+
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.withContext
+import java.io.File
+
+@Suppress("InjectDispatcher")
+internal actual suspend fun getDayInput(day: Int): String = withContext(Dispatchers.IO) {
+    File(System.getenv("AOC2023_DATADIR")?.ifEmpty { null } ?: ".", "day$day.txt").readText()
+}
diff --git a/kt/aoc2023-exe/src/jvmMain/kotlin/com/github/ephemient/aoc2023/exe/JvmMain.kt b/kt/aoc2023-exe/src/jvmMain/kotlin/com/github/ephemient/aoc2023/exe/JvmMain.kt
new file mode 100644
index 00000000..ffad420d
--- /dev/null
+++ b/kt/aoc2023-exe/src/jvmMain/kotlin/com/github/ephemient/aoc2023/exe/JvmMain.kt
@@ -0,0 +1,5 @@
+@file:JvmName("Main")
+
+package com.github.ephemient.aoc2023.exe
+
+suspend fun main(vararg args: String): Unit = mainImpl(*args)
diff --git a/kt/aoc2023-exe/src/nativeMain/kotlin/com/github/ephemient/aoc2023/exe/IO.kt b/kt/aoc2023-exe/src/nativeMain/kotlin/com/github/ephemient/aoc2023/exe/IO.kt
new file mode 100644
index 00000000..00cb2384
--- /dev/null
+++ b/kt/aoc2023-exe/src/nativeMain/kotlin/com/github/ephemient/aoc2023/exe/IO.kt
@@ -0,0 +1,16 @@
+package com.github.ephemient.aoc2023.exe
+
+import kotlinx.cinterop.ExperimentalForeignApi
+import kotlinx.cinterop.toKString
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.IO
+import kotlinx.coroutines.withContext
+import okio.Path.Companion.toPath
+import okio.buffer
+import platform.posix.getenv
+
+@OptIn(ExperimentalForeignApi::class)
+internal actual suspend fun getDayInput(day: Int): String = withContext(Dispatchers.IO) {
+    val dataDir = (getenv("AOC2023_DATADIR")?.toKString()?.ifEmpty { null } ?: ".").toPath()
+    okio.FileSystem.SYSTEM.source(dataDir / "day$day.txt").buffer().readUtf8()
+}
diff --git a/kt/aoc2023-exe/src/nativeMain/kotlin/com/github/ephemient/aoc2023/exe/NativeMain.kt b/kt/aoc2023-exe/src/nativeMain/kotlin/com/github/ephemient/aoc2023/exe/NativeMain.kt
new file mode 100644
index 00000000..cae67265
--- /dev/null
+++ b/kt/aoc2023-exe/src/nativeMain/kotlin/com/github/ephemient/aoc2023/exe/NativeMain.kt
@@ -0,0 +1,7 @@
+package com.github.ephemient.aoc2023.exe
+
+import kotlinx.coroutines.runBlocking
+
+fun main(vararg args: String): Unit = runBlocking {
+    mainImpl(*args)
+}
diff --git a/kt/aoc2023-lib/build.gradle.kts b/kt/aoc2023-lib/build.gradle.kts
new file mode 100644
index 00000000..d140b6f2
--- /dev/null
+++ b/kt/aoc2023-lib/build.gradle.kts
@@ -0,0 +1,29 @@
+plugins {
+    kotlin("multiplatform")
+    id("com.github.ephemient.aoc2023.detekt")
+    id("com.github.ephemient.aoc2023.kotlin.multiplatform.jvm.platform")
+    id("com.github.ephemient.aoc2023.kotlin.multiplatform.native.platforms")
+}
+
+kotlin {
+    sourceSets {
+        commonTest {
+            dependencies {
+                implementation(kotlin("test"))
+                implementation(libs.kotlinx.coroutines.test)
+            }
+        }
+
+        jvmTest {
+            dependencies {
+                implementation(kotlin("test-junit5"))
+                implementation(libs.junit.jupiter.api)
+                runtimeOnly(libs.junit.jupiter.engine)
+            }
+        }
+    }
+}
+
+tasks.jvmTest {
+    useJUnitPlatform()
+}
diff --git a/kt/aoc2023-lib/src/commonMain/kotlin/com/github/ephemient/aoc2023/Day1.kt b/kt/aoc2023-lib/src/commonMain/kotlin/com/github/ephemient/aoc2023/Day1.kt
new file mode 100644
index 00000000..f7978931
--- /dev/null
+++ b/kt/aoc2023-lib/src/commonMain/kotlin/com/github/ephemient/aoc2023/Day1.kt
@@ -0,0 +1,33 @@
+package com.github.ephemient.aoc2023
+
+class Day1(input: String) {
+    private val lines = input.lines()
+
+    fun part1() = solve(digits)
+
+    fun part2() = solve(extendedDigits)
+
+    private fun solve(values: Collection<IndexedValue<String>>): Int = lines.sumOf { line ->
+        val subset = values.filter { it.value in line }
+        if (subset.isNotEmpty()) {
+            10 * subset.minBy { line.indexOf(it.value) }.index + subset.maxBy { line.lastIndexOf(it.value) }.index
+        } else {
+            0
+        }
+    }
+
+    companion object {
+        private val digits = List(10) { IndexedValue(it, it.toString()) }
+        private val extendedDigits = digits + listOf(
+            IndexedValue(1, "one"),
+            IndexedValue(2, "two"),
+            IndexedValue(3, "three"),
+            IndexedValue(4, "four"),
+            IndexedValue(5, "five"),
+            IndexedValue(6, "six"),
+            IndexedValue(7, "seven"),
+            IndexedValue(8, "eight"),
+            IndexedValue(9, "nine"),
+        )
+    }
+}
diff --git a/kt/aoc2023-lib/src/commonMain/kotlin/com/github/ephemient/aoc2023/Days.kt b/kt/aoc2023-lib/src/commonMain/kotlin/com/github/ephemient/aoc2023/Days.kt
new file mode 100644
index 00000000..d8c10b03
--- /dev/null
+++ b/kt/aoc2023-lib/src/commonMain/kotlin/com/github/ephemient/aoc2023/Days.kt
@@ -0,0 +1,11 @@
+package com.github.ephemient.aoc2023
+
+val days = listOf(
+    Day(1) { with(Day1(it)) { listOf({ part1() }, { part2() }) } },
+)
+
+data class Day(
+    val day: Int,
+    val name: String = day.toString(),
+    val solver: (String) -> List<suspend () -> Any?>,
+)
diff --git a/kt/aoc2023-lib/src/commonTest/kotlin/com/github/ephemient/aoc2023/Day1Test.kt b/kt/aoc2023-lib/src/commonTest/kotlin/com/github/ephemient/aoc2023/Day1Test.kt
new file mode 100644
index 00000000..f6a33ce6
--- /dev/null
+++ b/kt/aoc2023-lib/src/commonTest/kotlin/com/github/ephemient/aoc2023/Day1Test.kt
@@ -0,0 +1,38 @@
+package com.github.ephemient.aoc2023
+
+import kotlinx.coroutines.test.runTest
+import kotlin.test.Test
+import kotlin.test.assertEquals
+
+class Day1Test {
+    @Test
+    fun part1() = runTest {
+        assertEquals(142, Day1(example1).part1())
+    }
+
+    @Test
+    fun part2() = runTest {
+        assertEquals(281, Day1(example2).part2())
+    }
+
+    companion object {
+        private val example1 =
+            """
+            |1abc2
+            |pqr3stu8vwx
+            |a1b2c3d4e5f
+            |treb7uchet
+            |""".trimMargin()
+
+        private val example2 =
+            """
+            |two1nine
+            |eightwothree
+            |abcone2threexyz
+            |xtwone3four
+            |4nineeightseven2
+            |zoneight234
+            |7pqrstsixteen
+            |""".trimMargin()
+    }
+}
diff --git a/kt/build.gradle.kts b/kt/build.gradle.kts
new file mode 100644
index 00000000..a33f423b
--- /dev/null
+++ b/kt/build.gradle.kts
@@ -0,0 +1,15 @@
+plugins {
+    alias(libs.plugins.kotlin.plugin.allopen) apply false
+    alias(libs.plugins.kotlinx.benchmark) apply false
+    alias(libs.plugins.dependency.updates)
+    id("com.github.ephemient.aoc2023.detekt")
+}
+
+tasks.detekt {
+    setSource(files().apply { from(layout.projectDirectory.asFileTree.matching { include("*.kts") }) })
+}
+
+tasks.dependencyUpdates {
+    revision = "release"
+    gradleReleaseChannel = "current"
+}
diff --git a/kt/buildSrc/build.gradle.kts b/kt/buildSrc/build.gradle.kts
new file mode 100644
index 00000000..7f872bbd
--- /dev/null
+++ b/kt/buildSrc/build.gradle.kts
@@ -0,0 +1,27 @@
+plugins {
+    `kotlin-dsl`
+}
+
+group = "com.github.ephemient.aoc2023.build-logic"
+
+gradlePlugin {
+    plugins {
+        create("KotlinMultiplatformDefaultHierarchyPlugin") {
+            id = "com.github.ephemient.aoc2023.kotlin.multiplatform.base"
+            implementationClass = "com.github.ephemient.aoc2023.buildsrc.KotlinMultiplatformBasePlugin"
+        }
+        create("KotlinMultiplatformJvmPlatformPlugin") {
+            id = "com.github.ephemient.aoc2023.kotlin.multiplatform.jvm.platform"
+            implementationClass = "com.github.ephemient.aoc2023.buildsrc.KotlinMultiplatformJvmPlatformPlugin"
+        }
+        create("KotlinMultiplatformNativePlatformsPlugin") {
+            id = "com.github.ephemient.aoc2023.kotlin.multiplatform.native.platforms"
+            implementationClass = "com.github.ephemient.aoc2023.buildsrc.KotlinMultiplatformNativePlatformsPlugin"
+        }
+    }
+}
+
+dependencies {
+    implementation(kotlin("gradle-plugin", libs.versions.kotlin.get()))
+    implementation(libs.detekt.plugin)
+}
diff --git a/kt/buildSrc/settings.gradle.kts b/kt/buildSrc/settings.gradle.kts
new file mode 100644
index 00000000..f7b41ed1
--- /dev/null
+++ b/kt/buildSrc/settings.gradle.kts
@@ -0,0 +1,20 @@
+pluginManagement {
+    repositories {
+        mavenCentral()
+        gradlePluginPortal()
+    }
+}
+
+dependencyResolutionManagement {
+    repositories {
+        mavenCentral()
+    }
+
+    versionCatalogs {
+        create("libs") {
+            from(files("../gradle/libs.versions.toml"))
+        }
+    }
+}
+
+rootProject.name = "buildSrc"
diff --git a/kt/buildSrc/src/main/kotlin/com.github.ephemient.aoc2023.detekt.gradle.kts b/kt/buildSrc/src/main/kotlin/com.github.ephemient.aoc2023.detekt.gradle.kts
new file mode 100644
index 00000000..f439333b
--- /dev/null
+++ b/kt/buildSrc/src/main/kotlin/com.github.ephemient.aoc2023.detekt.gradle.kts
@@ -0,0 +1,27 @@
+import io.gitlab.arturbosch.detekt.Detekt
+
+plugins {
+    `lifecycle-base`
+    id("io.gitlab.arturbosch.detekt")
+}
+
+dependencies {
+    versionCatalogs.named("libs").findBundle("detekt-plugins").ifPresent {
+        detektPlugins(it)
+    }
+}
+
+detekt {
+    config.from(rootProject.file("detekt.yml"))
+    buildUponDefaultConfig = true
+    autoCorrect = System.getenv("CI").isNullOrEmpty()
+}
+
+val detektAll by tasks.registering {
+    group = LifecycleBasePlugin.VERIFICATION_GROUP
+    dependsOn(tasks.withType<Detekt>())
+}
+
+tasks.check {
+    dependsOn(detektAll)
+}
diff --git a/kt/buildSrc/src/main/kotlin/com/github/ephemient/aoc2023/buildsrc/KotlinMultiplatformPlugins.kt b/kt/buildSrc/src/main/kotlin/com/github/ephemient/aoc2023/buildsrc/KotlinMultiplatformPlugins.kt
new file mode 100644
index 00000000..f3bc3333
--- /dev/null
+++ b/kt/buildSrc/src/main/kotlin/com/github/ephemient/aoc2023/buildsrc/KotlinMultiplatformPlugins.kt
@@ -0,0 +1,38 @@
+package com.github.ephemient.aoc2023.buildsrc
+
+import org.gradle.api.Plugin
+import org.gradle.api.Project
+import org.gradle.kotlin.dsl.apply
+import org.gradle.kotlin.dsl.getValue
+import org.jetbrains.kotlin.gradle.dsl.KotlinMultiplatformExtension
+
+class KotlinMultiplatformBasePlugin : Plugin<Project> {
+    override fun apply(target: Project) {
+        target.pluginManager.withPlugin("org.jetbrains.kotlin.multiplatform") {
+            val kotlin: KotlinMultiplatformExtension by target.extensions
+            kotlin.applyDefaultHierarchyTemplate()
+        }
+    }
+}
+
+class KotlinMultiplatformJvmPlatformPlugin : Plugin<Project> {
+    override fun apply(target: Project) {
+        target.apply<KotlinMultiplatformBasePlugin>()
+        target.pluginManager.withPlugin("org.jetbrains.kotlin.multiplatform") {
+            val kotlin: KotlinMultiplatformExtension by target.extensions
+            kotlin.jvm()
+        }
+    }
+}
+
+class KotlinMultiplatformNativePlatformsPlugin : Plugin<Project> {
+    override fun apply(target: Project) {
+        target.apply<KotlinMultiplatformBasePlugin>()
+        target.pluginManager.withPlugin("org.jetbrains.kotlin.multiplatform") {
+            val kotlin: KotlinMultiplatformExtension by target.extensions
+            kotlin.linuxX64()
+            kotlin.macosX64()
+            kotlin.macosArm64()
+        }
+    }
+}
diff --git a/kt/detekt.yml b/kt/detekt.yml
new file mode 100644
index 00000000..a1e6cd29
--- /dev/null
+++ b/kt/detekt.yml
@@ -0,0 +1,3 @@
+style:
+  MagicNumber:
+    active: false
diff --git a/kt/gradle.properties b/kt/gradle.properties
new file mode 100644
index 00000000..87519186
--- /dev/null
+++ b/kt/gradle.properties
@@ -0,0 +1,6 @@
+kotlin.code.style=official
+org.gradle.caching=true
+org.gradle.configuration-cache=true
+org.gradle.java.installations.fromEnv=GRAALVM_HOME
+org.gradle.jvmargs=-Xmx768m -XX:+UseParallelGC
+org.gradle.parallel=true
diff --git a/kt/gradle/libs.versions.toml b/kt/gradle/libs.versions.toml
new file mode 100644
index 00000000..ddc53793
--- /dev/null
+++ b/kt/gradle/libs.versions.toml
@@ -0,0 +1,30 @@
+[versions]
+dependency-updates = "0.50.0"
+detekt = "1.23.4"
+graal-sdk = "23.1.1"
+junit-jupiter = "5.10.1"
+kotlin = "1.9.21"
+kotlinx-benchmark = "0.4.9"
+kotlinx-coroutines = "1.7.3"
+okio = "3.6.0"
+native-image-plugin = "0.9.28"
+
+[plugins]
+dependency-updates = { id = "com.github.ben-manes.versions", version.ref = "dependency-updates" }
+kotlin-plugin-allopen = { id = "org.jetbrains.kotlin.plugin.allopen", version.ref = "kotlin" }
+kotlinx-benchmark = { id = "org.jetbrains.kotlinx.benchmark", version.ref = "kotlinx-benchmark" }
+native-image = { id = "org.graalvm.buildtools.native", version.ref = "native-image-plugin" }
+
+[libraries]
+detekt-formatting = { module = "io.gitlab.arturbosch.detekt:detekt-formatting", version.ref = "detekt" }
+detekt-plugin = { module = "io.gitlab.arturbosch.detekt:detekt-gradle-plugin", version.ref = "detekt" }
+graal-sdk = { module = "org.graalvm.sdk:graal-sdk", version.ref = "graal-sdk" }
+junit-jupiter-api = { module = "org.junit.jupiter:junit-jupiter-api", version.ref = "junit-jupiter" }
+junit-jupiter-engine = { module = "org.junit.jupiter:junit-jupiter-engine", version.ref = "junit-jupiter" }
+kotlinx-benchmark = { module = "org.jetbrains.kotlinx:kotlinx-benchmark-runtime", version.ref = "kotlinx-benchmark" }
+kotlinx-coroutines = { module = "org.jetbrains.kotlinx:kotlinx-coroutines-core", version.ref = "kotlinx-coroutines" }
+kotlinx-coroutines-test = { module = "org.jetbrains.kotlinx:kotlinx-coroutines-test", version.ref = "kotlinx-coroutines" }
+okio = { module = "com.squareup.okio:okio", version.ref = "okio" }
+
+[bundles]
+detekt-plugins = ["detekt-formatting"]
diff --git a/kt/gradle/wrapper/gradle-wrapper.jar b/kt/gradle/wrapper/gradle-wrapper.jar
new file mode 100644
index 00000000..d64cd491
Binary files /dev/null and b/kt/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/kt/gradle/wrapper/gradle-wrapper.properties b/kt/gradle/wrapper/gradle-wrapper.properties
new file mode 100644
index 00000000..1af9e093
--- /dev/null
+++ b/kt/gradle/wrapper/gradle-wrapper.properties
@@ -0,0 +1,7 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.5-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists
diff --git a/kt/gradlew b/kt/gradlew
new file mode 100755
index 00000000..1aa94a42
--- /dev/null
+++ b/kt/gradlew
@@ -0,0 +1,249 @@
+#!/bin/sh
+
+#
+# Copyright © 2015-2021 the original authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+##############################################################################
+#
+#   Gradle start up script for POSIX generated by Gradle.
+#
+#   Important for running:
+#
+#   (1) You need a POSIX-compliant shell to run this script. If your /bin/sh is
+#       noncompliant, but you have some other compliant shell such as ksh or
+#       bash, then to run this script, type that shell name before the whole
+#       command line, like:
+#
+#           ksh Gradle
+#
+#       Busybox and similar reduced shells will NOT work, because this script
+#       requires all of these POSIX shell features:
+#         * functions;
+#         * expansions «$var», «${var}», «${var:-default}», «${var+SET}»,
+#           «${var#prefix}», «${var%suffix}», and «$( cmd )»;
+#         * compound commands having a testable exit status, especially «case»;
+#         * various built-in commands including «command», «set», and «ulimit».
+#
+#   Important for patching:
+#
+#   (2) This script targets any POSIX shell, so it avoids extensions provided
+#       by Bash, Ksh, etc; in particular arrays are avoided.
+#
+#       The "traditional" practice of packing multiple parameters into a
+#       space-separated string is a well documented source of bugs and security
+#       problems, so this is (mostly) avoided, by progressively accumulating
+#       options in "$@", and eventually passing that to Java.
+#
+#       Where the inherited environment variables (DEFAULT_JVM_OPTS, JAVA_OPTS,
+#       and GRADLE_OPTS) rely on word-splitting, this is performed explicitly;
+#       see the in-line comments for details.
+#
+#       There are tweaks for specific operating systems such as AIX, CygWin,
+#       Darwin, MinGW, and NonStop.
+#
+#   (3) This script is generated from the Groovy template
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       within the Gradle project.
+#
+#       You can find Gradle at https://github.com/gradle/gradle/.
+#
+##############################################################################
+
+# Attempt to set APP_HOME
+
+# Resolve links: $0 may be a link
+app_path=$0
+
+# Need this for daisy-chained symlinks.
+while
+    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+    [ -h "$app_path" ]
+do
+    ls=$( ls -ld "$app_path" )
+    link=${ls#*' -> '}
+    case $link in             #(
+      /*)   app_path=$link ;; #(
+      *)    app_path=$APP_HOME$link ;;
+    esac
+done
+
+# This is normally unused
+# shellcheck disable=SC2034
+APP_BASE_NAME=${0##*/}
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD=maximum
+
+warn () {
+    echo "$*"
+} >&2
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+} >&2
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "$( uname )" in                #(
+  CYGWIN* )         cygwin=true  ;; #(
+  Darwin* )         darwin=true  ;; #(
+  MSYS* | MINGW* )  msys=true    ;; #(
+  NONSTOP* )        nonstop=true ;;
+esac
+
+CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
+
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+        # IBM's JDK on AIX uses strange locations for the executables
+        JAVACMD=$JAVA_HOME/jre/sh/java
+    else
+        JAVACMD=$JAVA_HOME/bin/java
+    fi
+    if [ ! -x "$JAVACMD" ] ; then
+        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD=java
+    if ! command -v java >/dev/null 2>&1
+    then
+        die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+fi
+
+# Increase the maximum file descriptors if we can.
+if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
+    case $MAX_FD in #(
+      max*)
+        # In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC2039,SC3045
+        MAX_FD=$( ulimit -H -n ) ||
+            warn "Could not query maximum file descriptor limit"
+    esac
+    case $MAX_FD in  #(
+      '' | soft) :;; #(
+      *)
+        # In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC2039,SC3045
+        ulimit -n "$MAX_FD" ||
+            warn "Could not set maximum file descriptor limit to $MAX_FD"
+    esac
+fi
+
+# Collect all arguments for the java command, stacking in reverse order:
+#   * args from the command line
+#   * the main class name
+#   * -classpath
+#   * -D...appname settings
+#   * --module-path (only if needed)
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, and GRADLE_OPTS environment variables.
+
+# For Cygwin or MSYS, switch paths to Windows format before running java
+if "$cygwin" || "$msys" ; then
+    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+
+    JAVACMD=$( cygpath --unix "$JAVACMD" )
+
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    for arg do
+        if
+            case $arg in                                #(
+              -*)   false ;;                            # don't mess with options #(
+              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+                    [ -e "$t" ] ;;                      #(
+              *)    false ;;
+            esac
+        then
+            arg=$( cygpath --path --ignore --mixed "$arg" )
+        fi
+        # Roll the args list around exactly as many times as the number of
+        # args, so each arg winds up back in the position where it started, but
+        # possibly modified.
+        #
+        # NB: a `for` loop captures its iteration list before it begins, so
+        # changing the positional parameters here affects neither the number of
+        # iterations, nor the values presented in `arg`.
+        shift                   # remove old arg
+        set -- "$@" "$arg"      # push replacement arg
+    done
+fi
+
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
+
+set -- \
+        "-Dorg.gradle.appname=$APP_BASE_NAME" \
+        -classpath "$CLASSPATH" \
+        org.gradle.wrapper.GradleWrapperMain \
+        "$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+    die "xargs is not available"
+fi
+
+# Use "xargs" to parse quoted args.
+#
+# With -n1 it outputs one arg per line, with the quotes and backslashes removed.
+#
+# In Bash we could simply go:
+#
+#   readarray ARGS < <( xargs -n1 <<<"$var" ) &&
+#   set -- "${ARGS[@]}" "$@"
+#
+# but POSIX shell has neither arrays nor command substitution, so instead we
+# post-process each arg (as a line of input to sed) to backslash-escape any
+# character that might be a shell metacharacter, then use eval to reverse
+# that process (while maintaining the separation between arguments), and wrap
+# the whole thing up as a single "set" statement.
+#
+# This will of course break if any of these variables contains a newline or
+# an unmatched quote.
+#
+
+eval "set -- $(
+        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+        xargs -n1 |
+        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+        tr '\n' ' '
+    )" '"$@"'
+
+exec "$JAVACMD" "$@"
diff --git a/kt/gradlew.bat b/kt/gradlew.bat
new file mode 100644
index 00000000..6689b85b
--- /dev/null
+++ b/kt/gradlew.bat
@@ -0,0 +1,92 @@
+@rem
+@rem Copyright 2015 the original author or authors.
+@rem
+@rem Licensed under the Apache License, Version 2.0 (the "License");
+@rem you may not use this file except in compliance with the License.
+@rem You may obtain a copy of the License at
+@rem
+@rem      https://www.apache.org/licenses/LICENSE-2.0
+@rem
+@rem Unless required by applicable law or agreed to in writing, software
+@rem distributed under the License is distributed on an "AS IS" BASIS,
+@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+@rem See the License for the specific language governing permissions and
+@rem limitations under the License.
+@rem
+
+@if "%DEBUG%"=="" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" setlocal
+
+set DIRNAME=%~dp0
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Resolve any "." and ".." in APP_HOME to make it shorter.
+for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if %ERRORLEVEL% equ 0 goto execute
+
+echo.
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto execute
+
+echo.
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:execute
+@rem Setup the command line
+
+set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
+
+
+@rem Execute Gradle
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %*
+
+:end
+@rem End local scope for the variables with windows NT shell
+if %ERRORLEVEL% equ 0 goto mainEnd
+
+:fail
+rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
+rem the _cmd.exe /c_ return code!
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega
diff --git a/kt/settings.gradle.kts b/kt/settings.gradle.kts
new file mode 100644
index 00000000..9e35b41a
--- /dev/null
+++ b/kt/settings.gradle.kts
@@ -0,0 +1,17 @@
+enableFeaturePreview("TYPESAFE_PROJECT_ACCESSORS")
+
+pluginManagement {
+    repositories {
+        mavenCentral()
+        gradlePluginPortal()
+    }
+}
+
+dependencyResolutionManagement {
+    repositories {
+        mavenCentral()
+    }
+}
+
+rootProject.name = "aoc2023"
+include("aoc2023-exe", "aoc2023-lib")