--- a/progs/lecture2.scala	Tue Dec 03 11:07:09 2019 +0000
+++ b/progs/lecture2.scala	Mon Jan 27 10:18:13 2020 +0000
@@ -505,6 +505,14 @@
 combs("abc".toList, 2)
 
 
+// When writing recursive functions you have to
+// think about three points
+// 
+// - How to start with a recursive function
+// - How to communicate between recursive calls
+// - Exit conditions
+
+
 
 // A Recursive Web Crawler / Email Harvester
 //===========================================