How do they do it?

I don't understand how seemingly innocent 2 1/2 year old twins can get themselves into so much mischief. Today as I was playing with Cooper in the living room I hear some type of tupperware container bounce on the floor. Okay, I think, I'll check on it in a little while. The twins are always getting into the tupperware drawer, no big deal. So after about 10 minutes I go into the kitchen to get a bottle for Cooper, having forgotten the sound I had heard earlier, and what do I see all over the floor and Cooper's diaper bag (not to mention all the diapers, clothes, toys, and crevices inside the diaper bag)? Powered formula. They had somehow managed to open up the divided formula container that is kept in Cooper's bag and spill 3 eight ounce bottles worth of powered formula all over the place. Isn't it hard enough for me to keep the house clean without having all these extra chores to do????!!!!