Very good advice. We do use such a system often in other areas. They share the trampoline by hopping on, counting to 10 and hopping off. I use a timer to tell them when their time is up for certain activities. Aside from the location problem is the fact that my mom expressly gave the computer to him and he sees it as his. He knows he has to share but still sees it as his. But maybe timed turns will work in the short term. I think I will try this tonight.