diff --git a/advent-of-typescript/2023/day_17.ts b/advent-of-typescript/2023/day_17.ts
new file mode 100644
index 0000000..6286f13
--- /dev/null
+++ b/advent-of-typescript/2023/day_17.ts
@@ -0,0 +1,75 @@
+import { Equal, Expect } from "type-testing";
+
+/* -----------------------------------------------------------------------------------------------
+ * Code here
+ * -----------------------------------------------------------------------------------------------*/
+
+type RockPaperScissors = "👊🏻" | "🖐🏾" | "✌🏽";
+
+type WhoWins<
+  O extends RockPaperScissors,
+  M extends RockPaperScissors,
+> = O extends M
+  ? "draw"
+  : M extends "🖐🏾"
+    ? O extends "👊🏻"
+      ? "win"
+      : "lose"
+    : M extends "👊🏻"
+      ? O extends "✌🏽"
+        ? "win"
+        : "lose"
+      : M extends "✌🏽"
+        ? O extends "🖐🏾"
+          ? "win"
+          : "lose"
+        : never;
+
+/* -----------------------------------------------------------------------------------------------
+ * Do not edit below this line
+ * -----------------------------------------------------------------------------------------------*/
+
+type test_0_actual = WhoWins<"👊🏻", "🖐🏾">;
+//   ^?
+type test_0_expected = "win";
+type test_0 = Expect<Equal<test_0_expected, test_0_actual>>;
+
+type test_1_actual = WhoWins<"👊🏻", "✌🏽">;
+//   ^?
+type test_1_expected = "lose";
+type test_1 = Expect<Equal<test_1_expected, test_1_actual>>;
+
+type test_2_actual = WhoWins<"👊🏻", "👊🏻">;
+//   ^?
+type test_2_expected = "draw";
+type test_2 = Expect<Equal<test_2_expected, test_2_actual>>;
+
+type test_3_actual = WhoWins<"🖐🏾", "👊🏻">;
+//   ^?
+type test_3_expected = "lose";
+type test_3 = Expect<Equal<test_3_expected, test_3_actual>>;
+
+type test_4_actual = WhoWins<"🖐🏾", "✌🏽">;
+//   ^?
+type test_4_expected = "win";
+type test_4 = Expect<Equal<test_4_expected, test_4_actual>>;
+
+type test_5_actual = WhoWins<"🖐🏾", "🖐🏾">;
+//   ^?
+type test_5_expected = "draw";
+type test_5 = Expect<Equal<test_5_expected, test_5_actual>>;
+
+type test_6_actual = WhoWins<"✌🏽", "👊🏻">;
+//   ^?
+type test_6_expected = "win";
+type test_6 = Expect<Equal<test_6_expected, test_6_actual>>;
+
+type test_7_actual = WhoWins<"✌🏽", "✌🏽">;
+//   ^?
+type test_7_expected = "draw";
+type test_7 = Expect<Equal<test_7_expected, test_7_actual>>;
+
+type test_8_actual = WhoWins<"✌🏽", "🖐🏾">;
+//   ^?
+type test_8_expected = "lose";
+type test_8 = Expect<Equal<test_8_expected, test_8_actual>>;