Ok, here is a quiz that Tristan has in his new book that he received for his birthday. Each rectangle is a house and the circles stand for water, electricity, and gas. Grab a paper and pencil and draw your own sketch.
Draw a pipe (line) so water goes to each house and gas and electricity go to each house. The catch is: the pipes can NOT cross each other. The circles and rectangles can go any where on your paper. I will tell the solution soon!
Solution: It's impossible