Original instructions in original project. Thanks gtoal, I'm guessing travelling salesman has been so well studied that any technique is either already known or not very good. But anyway here's my stab at it.
Basic strategy: 1. Sort by distance from centre; 2 Subject to 3 and 4, join each city (starting with furthest from centre) to its two closest neighbours. 3. Avoid creating loop till end. 4. Can't join to city already linked to two others. Then some improvement by (a) uncrossing crossed lines and (b) checking whether individual points would be better inserted into a line segment elsewhere.
