I take no credit for this activity whatsoever. I saw the basic idea on Pinterest while looking for something else (for some reason I never pinned it), but I remembered the idea. In Geometry, students need to know cross-sections (G-GMD 4 - Identify the shapes of two-dimensional cross-sections of three-dimensional objects). To give students a better idea of cross-sections, I always explained it as taking a slice of a solid. The idea I found literally has students taking slices of shapes.
Tip: Start with the cylinder. The Play-Doh is pretty much in a cylinder shape when you take it out of its container.