Now that the big kid is in after-school programs, he has a lot of varied interests and materials to match.  He is part of an advance Lego class, as well as a robot class.  The teachers sent home the kits for the Lego and the robot.  When the Lego stuff came home, the big kid wanted to play with it.  Although I didn't like the idea, I let him.  We locked him in the master bedroom where he could build without being hassled by the toddler.  Once he was finished, he was proud of what he accomplished, and came out to show u=\ \n \ what he managed to do all on his own.  There was tiny, probably important, bits of Lego all over the room, and the toddler wanted to play with (ie break) the remote control truck that the big kid built.  This went on for a few days, until I packed it all up and put it where no one can reach