Many-to-Many Shape Sorter (Shadow Sets)
Inspired by a puzzle set by East Dorset MathsJam https://mathsjam.com/cities/eastdorset/
Each of these objects casts a different set of shadows when viewed from the top, front and side.
The sets are:
circle, square, triangle
circle, triangle, triangle
circle, square, circle
circle, rectangle, hexagon
circle, triangle, hexagon
You can also print a shape sorter for playing with the objects. Each object fits snugly through at least two holes, and each hole will accept one or more objects.