diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 9881ff4..9313112 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -7134,7 +7134,7 @@ CREATE TYPE rainbow AS ENUM ('red', 'orange', 'yellow', 'green', 'blue', 'purple
&&
- Overlaps?
+ Overlaps? One point in common makes this true.
box '((0,0),(1,1))' && box '((0,0),(2,2))'