My 17 month old loves to stack the buckets up then knock them down, over and over again.  We haven't talked much about the pictures on the sides of the buckets, showing opposites (short vs. tall, none vs. many, etc.).  He also loves to carry the biggest bucket like a purse and put stuff in it.  These are very durable (he is tough on things) and I would highly recommend them.  I think he will be playing with them for months to come.