Getting All the Utilities to Each House

Date: 17 May 1995 08:43:27 -0400
From: Anonymous
Subject: Puzzle

I've been stumped-here's the problem: Draw 3 one inch squares representing
houses horizontally across the page.  Draw three circles, one under each
square.  Number your squares and put a G for gas , E for electric, and W for
water in each circle.  Your job is to connect each utility to each home
WITHOUT crossing any lines. You may not pass a line through a house or
other utility circle. Leave an inch and a half between each house. Put each
circle an inch below each square.  

Mr. Borstein.

Date: 9 Jun 1995 11:05:33 -0400
From: Dr. Ken
Subject: Puzzle

Hello there!

I'm afraid your problem kind of got lost in the shuffle of problems.  Also,
I hope I can make you feel a little better about the fact that you couldn't
solve it, because there is no solution possible.  

What's neat (and you might want to pass this along as a challenge to your
students) is that while the problem can't be solved in the Euclidean plane,
it CAN be done on the surface of a torus (a doughnut).  See if your students
can figure out why.

-K