X-Git-Url: http://lambda.jimpryor.net/git/gitweb.cgi?p=lambda.git;a=blobdiff_plain;f=miscellaneous_lambda_challenges_and_advanced_topics.mdwn;h=a3d65e2055720ff923ab37eb6fbebb221e919201;hp=a4ba9854def7149afb409815a2dcb4c320b2e5e1;hb=cb31839ef2a0cea9b6138fa84d487ab7107328c2;hpb=58137a1e8e52e3c15790ab3209b4f217dcdd1ba4

diff --git a/miscellaneous_lambda_challenges_and_advanced_topics.mdwn b/miscellaneous_lambda_challenges_and_advanced_topics.mdwn
index a4ba9854..a3d65e20 100644
--- a/miscellaneous_lambda_challenges_and_advanced_topics.mdwn
+++ b/miscellaneous_lambda_challenges_and_advanced_topics.mdwn
@@ -496,8 +496,8 @@ can use.
 	Think about how you'd implement them in a more principled way. You could
 	use any of the version 1 -- version 5 implementation of lists as a model.
 
-	To keep things simple, I recommend starting with the version 3 pattern. And
-	stick to binary trees.
+	To keep things simple, we'll stick to binary trees. A node will either be a
+	*leaf* of the tree, or it will have exactly two children.
 
 	There are two kinds of trees to think about. In one sort of tree, it's only
 	the tree's *leaves* that are labeled: