hmm, I've been thinking this week about something.
I don't know if this has been done yet or not:
theme:
Limitations:
build a map with any block you wish to use. but keep in mind that you only have a limit on rescources.
(rescources would be the blocks you use. So like you got an option to use block 2-2-4 only 3 times etc...)
I don't know if anyone would be interested in this kind of theme. But it's a challenge imo.
force the players to use certain blocks less than usually and other blocks even more.
something else I came up with:
this is more an Oldschoolish theme:
Symetrical maps yup this has been done yet but how many years ago?