on it. picture a track that is very large... really large. let us say that it takes years for the drivers to race around the track. they get tired. sometimes they will get out of the car and put a new driver in. sometimes the new driver will get tired and the older driver will come back and get in again. so the race cars are filled with some experienced drivers and some not. as they go around the track, it might take them years to go around just one time.
let us say that there is a difficult portion of the track, one that is filled with holes. some don't 