Sync docs (#183)

exercises/practice/darts/.docs/instructions.md

@@ -1,6 +1,6 @@
 # Instructions
 
-Write a function that returns the earned points in a single toss of a Darts game.
+Calculate the points scored in a single toss of a Darts game.
 
 [Darts][darts] is a game where players throw darts at a [target][darts-target].
 
@@ -16,7 +16,7 @@ In our particular instance of the game, the target rewards 4 different amounts o
 The outer circle has a radius of 10 units (this is equivalent to the total radius for the entire target), the middle circle a radius of 5 units, and the inner circle a radius of 1.
 Of course, they are all centered at the same point — that is, the circles are [concentric][] defined by the coordinates (0, 0).
 
-Write a function that given a point in the target (defined by its [Cartesian coordinates][cartesian-coordinates] `x` and `y`, where `x` and `y` are [real][real-numbers]), returns the correct amount earned by a dart landing at that point.
+Given a point in the target (defined by its [Cartesian coordinates][cartesian-coordinates] `x` and `y`, where `x` and `y` are [real][real-numbers]), calculate the correct score earned by a dart landing at that point.
 
 ## Credit
 

exercises/practice/darts/.meta/config.json

@@ -13,6 +13,6 @@
       ".meta/example.red"
     ]
   },
-  "blurb": "Write a function that returns the earned points in a single toss of a Darts game.",
+  "blurb": "Calculate the points scored in a single toss of a Darts game.",
   "source": "Inspired by an exercise created by a professor Della Paolera in Argentina"
 }

exercises/practice/gigasecond/.meta/config.json

@@ -13,5 +13,7 @@
       ".meta/example.red"
     ]
   },
-  "blurb": "Given a moment, determine the moment that would be after a gigasecond has passed."
+  "blurb": "Given a moment, determine the moment that would be after a gigasecond has passed.",
+  "source": "Chapter 9 in Chris Pine's online Learn to Program tutorial.",
+  "source_url": "https://pine.fm/LearnToProgram/?Chapter=09"
 }

exercises/practice/hamming/.docs/instructions.md

@@ -1,6 +1,6 @@
 # Instructions
 
-Calculate the Hamming Distance between two DNA strands.
+Calculate the Hamming distance between two DNA strands.
 
 Your body is made up of cells that contain DNA.
 Those cells regularly wear out and need replacing, which they achieve by dividing into daughter cells.
@@ -9,18 +9,18 @@ In fact, the average human body experiences about 10 quadrillion cell divisions
 When cells divide, their DNA replicates too.
 Sometimes during this process mistakes happen and single pieces of DNA get encoded with the incorrect information.
 If we compare two strands of DNA and count the differences between them we can see how many mistakes occurred.
-This is known as the "Hamming Distance".
+This is known as the "Hamming distance".
 
-We read DNA using the letters C,A,G and T.
+We read DNA using the letters C, A, G and T.
 Two strands might look like this:
 
     GAGCCTACTAACGGGAT
     CATCGTAATGACGGCCT
     ^ ^ ^  ^ ^    ^^
 
-They have 7 differences, and therefore the Hamming Distance is 7.
+They have 7 differences, and therefore the Hamming distance is 7.
 
-The Hamming Distance is useful for lots of things in science, not just biology, so it's a nice phrase to be familiar with :)
+The Hamming distance is useful for lots of things in science, not just biology, so it's a nice phrase to be familiar with :)
 
 ## Implementation notes
 

exercises/practice/isogram/.meta/config.json

@@ -13,5 +13,7 @@
       ".meta/example.red"
     ]
   },
-  "blurb": "Determine if a word or phrase is an isogram."
+  "blurb": "Determine if a word or phrase is an isogram.",
+  "source": "Wikipedia",
+  "source_url": "https://en.wikipedia.org/wiki/Isogram"
 }

exercises/practice/space-age/.docs/instructions.md

@@ -1,25 +1,28 @@
 # Instructions
 
-Given an age in seconds, calculate how old someone would be on:
+Given an age in seconds, calculate how old someone would be on a planet in our Solar System.
 
-- Mercury: orbital period 0.2408467 Earth years
-- Venus: orbital period 0.61519726 Earth years
-- Earth: orbital period 1.0 Earth years, 365.25 Earth days, or 31557600 seconds
-- Mars: orbital period 1.8808158 Earth years
-- Jupiter: orbital period 11.862615 Earth years
-- Saturn: orbital period 29.447498 Earth years
-- Uranus: orbital period 84.016846 Earth years
-- Neptune: orbital period 164.79132 Earth years
+One Earth year equals 365.25 Earth days, or 31,557,600 seconds.
+If you were told someone was 1,000,000,000 seconds old, their age would be 31.69 Earth-years.
 
-So if you were told someone were 1,000,000,000 seconds old, you should
-be able to say that they're 31.69 Earth-years old.
+For the other planets, you have to account for their orbital period in Earth Years:
 
-If you're wondering why Pluto didn't make the cut, go watch [this YouTube video][pluto-video].
+| Planet  | Orbital period in Earth Years |
+| ------- | ----------------------------- |
+| Mercury | 0.2408467                     |
+| Venus   | 0.61519726                    |
+| Earth   | 1.0                           |
+| Mars    | 1.8808158                     |
+| Jupiter | 11.862615                     |
+| Saturn  | 29.447498                     |
+| Uranus  | 84.016846                     |
+| Neptune | 164.79132                     |
 
-Note: The actual length of one complete orbit of the Earth around the sun is closer to 365.256 days (1 sidereal year).
+~~~~exercism/note
+The actual length of one complete orbit of the Earth around the sun is closer to 365.256 days (1 sidereal year).
 The Gregorian calendar has, on average, 365.2425 days.
 While not entirely accurate, 365.25 is the value used in this exercise.
 See [Year on Wikipedia][year] for more ways to measure a year.
 
-[pluto-video]: https://www.youtube.com/watch?v=Z_2gbGXzFbs
 [year]: https://en.wikipedia.org/wiki/Year#Summary
+~~~~

exercises/practice/space-age/.docs/introduction.md

@@ -0,0 +1,20 @@
+# Introduction
+
+The year is 2525 and you've just embarked on a journey to visit all planets in the Solar System (Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune).
+The first stop is Mercury, where customs require you to fill out a form (bureaucracy is apparently _not_ Earth-specific).
+As you hand over the form to the customs officer, they scrutinize it and frown.
+"Do you _really_ expect me to believe you're just 50 years old?
+You must be closer to 200 years old!"
+
+Amused, you wait for the customs officer to start laughing, but they appear to be dead serious.
+You realize that you've entered your age in _Earth years_, but the officer expected it in _Mercury years_!
+As Mercury's orbital period around the sun is significantly shorter than Earth, you're actually a lot older in Mercury years.
+After some quick calculations, you're able to provide your age in Mercury Years.
+The customs officer smiles, satisfied, and waves you through.
+You make a mental note to pre-calculate your planet-specific age _before_ future customs checks, to avoid such mix-ups.
+
+~~~~exercism/note
+If you're wondering why Pluto didn't make the cut, go watch [this YouTube video][pluto-video].
+
+[pluto-video]: https://www.youtube.com/watch?v=Z_2gbGXzFbs
+~~~~

exercises/practice/yacht/.meta/config.json

@@ -14,6 +14,6 @@
     ]
   },
   "blurb": "Score a single throw of dice in the game Yacht.",
-  "source": "James Kilfiger, using wikipedia",
+  "source": "James Kilfiger, using Wikipedia",
   "source_url": "https://en.wikipedia.org/wiki/Yacht_(dice_game)"
 }