How do I build a curved wall? On my latest MOC I want to build a round tower.

This is a minifig-scale build, and the tower is going to have a diameter of about 20/30 studs.

How should I go about building the "curved" wall of the tower?
Inspired by Zhaph's wall, this one is made with 1x3 bricks.  It has a radius of 12 studs (24 studs diameter).



It is connected to the base by the last two studs on each end of the arc. The middle of the wall rests on tiles.  To complete the tower you can repeat this module 4 times and use 1x2 bricks to connect them (replacing the 1x1 end bricks).

This would not make a perfectly round wall, but it's pretty close.