This variation on my releaux triangle was inspired by user elspeth.
You could describe this as a triangle that rolls inside a square inside a triangle that rolls inside a square.

I have put ears on the outermost square to try to reduce warping, but this is so big and flat warping is probably inevitable. I think the ears (there to reduce warping) may throw the size over the limit for the cupcake...I think the raft goes over the screws. On request I can include a version without ears, or you can comment the line out in the scad file.

As with the previous thing, the resultant objects should not actually touch except for strings and raft. The gap is a 45 degree slot, which should be easy to pass a knife thorough. However, the tolerances may be tight, I tried to manually center the inner triangle a bit to help this.

Also, as with the previous thing, I suspect that this may tickle bugs in skeinforge. As with the parent part, skeinforge 35 and previous are known to not slice this object correctly, skipping some or all of the solid layers on some parts. (See Disrespective's picture.) Skeinforge 40 appears to overfill one layer.