[binary-search-tree] Four SVG graphs

exercises/binary-search-tree/description.md

@@ -19,29 +19,25 @@ All data in the left subtree is less than or equal to the current node's data, a
 
 For example, if we had a node containing the data 4, and we added the data 2, our tree would look like this:
 
-      4
-     /
-    2
+[A graph with root node 4 and a single child node 2.][4-2]
 
 If we then added 6, it would look like this:
 
-      4
-     / \
-    2   6
+[A graph with root node 4 and two child nodes 2 and 6.][4-2-6]
 
 If we then added 3, it would look like this
 
-       4
-     /   \
-    2     6
-     \
-      3
+[A graph with root node 4, two child nodes 2 and 6, and a grandchild node 3.][4-2-6-3]
 
 And if we then added 1, 5, and 7, it would look like this
 
-          4
-        /   \
-       /     \
-      2       6
-     / \     / \
-    1   3   5   7
+[A graph with root node 4, two child nodes 2 and 6, and four grandchild nodes 1, 3, 5 and 7.][4-2-6-1-3-5-7]
+
+## Credit
+
+The graphs are made by [habere-et-dispertire](https://exercism.org/profiles/habere-et-dispertire) using [PGF/TikZ](https://en.wikipedia.org/wiki/PGF/TikZ) by Till Tantau.
+
+[4-2]: https://exercism-v3-icons.s3.eu-west-2.amazonaws.com/images/exercises/binary-search-tree/tree-4-2.svg
+[4-2-6]: https://exercism-v3-icons.s3.eu-west-2.amazonaws.com/images/exercises/binary-search-tree/tree-4-2-6.svg
+[4-2-6-3]: https://exercism-v3-icons.s3.eu-west-2.amazonaws.com/images/exercises/binary-search-tree/tree-4-2-6-3.svg
+[4-2-6-1-3-5-7]: https://exercism-v3-icons.s3.eu-west-2.amazonaws.com/images/exercises/binary-search-tree/tree-4-2-6-1-3-5-7.svg