Your neighbor and his little boy were out in their front yard. The little boy has a toy car that he can sit in and ride (by pushing along with his feet). His father was working on his car, and you watched the father slide under his car to work underneath it with some tools. You looked over a few minutes later and giggled because the little boy also slid under his toy car and was using some of his plastic tools to "fix" the car. This demonstrates: