An interesting thing starts to happen as skip gets small.
Run your program with smallest = 2, biggest = 400, and skip = 2.
Did you get what you expected? If you did, you know too much and you
should go outside and play. For the rest of us, the unexpected
coolness on the screen is called a Moiré pattern, and it is the
result of a type of roundoff error called aliasing. For more
information on Moiré patterns, see the following web pages: