RotoPrism 3 (flat) is a "bandaged" puzzle with three axes of rotation, based on the geometry of the triangular dipyramid. It is essentially a shape modification of my Fracture-6 puzzle. The three axes are located at the center of each face around the equator of the puzzle. Every axis is capable of turning in 90 degree increments, but only when there are no triangular pieces on that face, otherwise the axis will be limited to 180 degree turns. This bandaging makes RotoPrism 3 very difficult to solve.
RotoPrism 3 comes as a DIY kit of parts, and you will need to supply your own stickers. The templates for the stickers are available in the instructions forum.
I recommend that unless you are familiar with the process of dyeing these parts, you purchase the puzzle in "Black Strong & Flexible". It costs a bit more than the white material, but it's worth it since the finished puzzle will look and work better. RotoPrism 3 also requires screws and springs to assemble. These can be purchased through a few different online puzzle sellers. The ones I used came from this shop. You'll need three screws and three springs.