Once upon a time there was a city that had no roads. Getting around the city was particularly difficult after rainstorms because the ground became very muddy—cars got stuck in the mud and people got their boots dirty. The mayor of the city decided that some of the streets must be paved, but didn’t want to spend more money than necessary because the city also wanted to build a swimming pool. The mayor therefore specified two conditions: (1) Enough streets must be paved so that it was possible for everyone to travel from their house to anyone else’s house by a route consisting only of paved roads, possibly via other houses, and (2) the paving should be accomplished at a minimum total cost Click on the roads and find out how to connect all the houses with the least amount of roads. When the stoplight changes green, you have connected all the houses.