Connect three towns with the shortest road — the obvious answer isn't optimal
You need to link three towns with roads so all three are connected, using the least total length of road. Simply drawing a road between every pair works, but it isn't optimal. A single extra junction point, placed somewhere in the empty space between the towns, can beat it. Where should that junction go?
Reveal the answer
The optimal junction sits where all three roads meet it at exactly 120-degree angles — the 'Steiner point.' For any triangle with no angle over 120 degrees, this beats every network built from just the three original towns. The problem is named after 19th-century mathematician Jakob Steiner, though the three-point case was studied even earlier by Fermat and Torricelli.