You and Simon each have two children: your daughter is 9 and your son is 10. It was a relatively warm day. Simon was tidying up the car, your son was playing with his ball on the grass in front of the porch, and your daughter, wearing a helmet and protective gear, was trying out her new skateboard near the stairs, in case she needed to hold onto the railing. You were carrying the laundry out to hang it up. You were walking slowly down the stairs and didn't see the skateboard. 