Gas Electricity Water Puzzle

This problem is perhaps the perfect introduction to graph theory.

Gas electricity water puzzle.

In a suburb three new houses all have to be connected to a gas red water blue and electricity green supply. Gas water electric to 3 houses. All houses should get their own gas water and electricity connection. A man has built three houses.

How do you connect mr angry mr beastly and mr cross to gas water and electricity without. Connecting gas water electric to three houses. The man wishes to connect all three houses to each of the gas water and electricity supplies. Since the puzzle is very famous we have chosen to present it in a new light.

Each year we receive an extraordinary number of letters regarding a classic route problem called water gas and electricity. Furthermore no connections may cross each other. Nearby there are gas water and electric plants. Unfortunately the pipes and cables must not cross each other.

Suppose there are three cottages on a plane or sphere and each needs to be connected to the water gas and electricity companies.