How to build a circular base without foundations?

[Supremist]

As the title says, how can I build a circular base, like a tower design but without using foundations as the base. The spot where I'm at isn't flat enough to place down enough triangle foundations to make it work so it would have to be built on pillars.

[sjskdjkfa]

I don't see what the problem is. I'd use something like this pattern: 

I thought maybe the problem would be putting a square ceiling and then extending out with triangle ceilings and 

at some point i put in a pillar and was able to extend it further... actually surprised the pillar went in the middle of the triangle at an angle, maybe if i were to get serious about this I'd tear that all down and start with a pillar and trianlge on the first one and have that at the highest point and try to make a flat layer (no pillars poking through the circle)

[Zapha]

If the ground is uneven, use the top-down method. First pillar normal, all others top-down builded. For a perfect snap a temporary pillar is placed into the ceiling which makes the right snap.