diff --git a/Main.go b/Main.go
index ee451dd..f618f8f 100644
--- a/Main.go
+++ b/Main.go
@@ -17,6 +17,8 @@ const (
 	largeGap = 3
 	monthWidth  = 7*dayWidth + 6*smallGap
 	monthHeight = (31+6+(7-1))/7 + 2
+	/* monthHeight is the height of a 31-day month starting on Sunday (month
+	name and weekdays included) */
 
 	titleHeight = smallGap + 1
 )