Mix a few cups of dry pasta in 2โ4 different shapes in one bowl. Put an empty muffin tin (or 3โ4 small bowls) next to it. Tray underneath.
Pick up one piece of pasta. Drop it into one of the wells. Pick up another shape, drop it into a different well. Step away.
Methodical, careful sorting. Re-sorting differently. Sometimes a 3-year-old will mix them up again at the end so they can re-sort.
Use tongs for harder fine-motor mode. Add a fourth shape later. Use food coloring to dye some pasta a different color for a color-sort version.