Merge pull request #701 from ninivert/patch-4

Added my contribution to Coding Challenge #107

Author: shiffman

_CodingChallenges/107-sandpiles.md

@@ -2,7 +2,7 @@
 title: "Sandpiles"
 video_number: 107
 date: 2018-06-18
-video_id: diGjw5tghYU
+video_id: "diGjw5tghYU"
 repository: /CC_107_sandpiles
 live_example: false
 
@@ -18,6 +18,14 @@ videos:
   - title: "Sandpiles"
     author: "Numberphile"
     video_id: "1MtEUErz7Gg"
+
+contributions:
+  - title: "Sandpiles JavaScript implementation"
+    author:
+      name: "Niels Vadot"
+      url: "https://nielsvadot.design/"
+    url: "https://ninivert.github.io/Sandpiles/"
+    source: "https://github.com/ninivert/Sandpiles"
 ---
 
 In this coding challenge, inspired by Numberphile I visualize "sandpiles" with Processing (Java).