Spirals are infinite. They go along a path that virtually never ends. The path, visually, is continuously shrinking into a potential point and its one of the easiest ways to visualize infinite, like fractals.
I have a question. If Higashikata was first than shouldn't he have been first to get water. He should've gotten it before Hot Pants even completed the race.
Actually... Technically you can ride whatever you want as long as it isn't a locomotive. The guys in the beginning were driving cars but stopped because they ran out of fuel.