Lots of the wooden ones fit together, ours is a combination from all over. We started the collection when DD1 was 2 and she has loved it since (just turned 5), it gets used often so well worth the investment. DD2 is 2 now and just starting to show interest in actually putting it all together and finds it easy enough to do so which is another reason we like it, frustrated 2yr olds are something we strongly try to avoid lol.