A way to make the AI harder?

[EyesOfNight]

Any way to make the AI expand faster and not build 3 spaces apart?

[kobayashi]

Pyramids

Settlers for their form of government not requiring food.

Make maintenance costs very high as its free for AI

not building cities three spaces apart would make the AI grow slower

[McMonkey]

If this is for a scenario you could create AI settlers through events. Whether the AI would actually use them to build cities is another matter. I tried this in a mod of Hellas but only a few of the settlers built cities, others just stood there for ages doing nothing!

[EyesOfNight]

Actually making the AI build 2 spaces apart would make them grow faster. My normal way of doing it is to give each AI 25 cities and then try to catch up.