I have a 13 month old in my care who has started flipping up the matress on her playpen at naptime...as well as taking off the sheet, throwing her socks over the edge, etc. Today I had to go in six times to put it back together and lie her down again, although she eventually gave up and went to sleep. I am hoping if I consistently do this without making eye contact or talking or giving her any attention for it, she will stop. However, I would love any other advice on this problem!