Sorting objects by shape and colour is an excellent beginning activity for infants & toddlers, and this set fits the bill. It includes a tray and eight pieces, including four blocks and four matching insets in coordinated colours. The pieces are made of solid rubberwood with water-based stains so their colour won't chip or flake off, and the tray is made of sawdust reclaimed from the manufacturing process. The tray features insets on one side to provide hints to the correct matches, and no insets on the other side to make the exercise a little more challenging. The tray measures 18 cm (about 7") square.