baby for 9 months now and can not seem to stack itself but Grandma that stacks and loves demolish the tower and also, it looks quans I put them into each other and try to do the same So he observes something and when I delmande him to put in, he understands and puts his balls in it to 9 months so I think it's a good observation period and after he makes one test, I do not let it trrop toy in the park when he finished because if he falls over while trying to asseoircomme it's kind of hard plastic, it could be bad but slightly sinonce product develops very different meaning baby.