Yeah - I think it's kinda like a maze when it's done.*
   [1]https://upload.wikimedia.org/wikipedia/commons/thumb/1/1d/Ulam_spiral_howto_all_numbers.svg/2000px-Ulam_spiral_howto_all_numbers.svg.png
   you take all of the numbers, starting with one, and go around
   and around. Imagine erasing all of the numbers that AREN'T prime
   numbers, so that there is only prime numbers left. That's what
   makes up the maze.

References

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   1. https://upload.wikimedia.org/wikipedia/commons/thumb/1/1d/Ulam_spiral_howto_all_numbers.svg/2000px-Ulam_spiral_howto_all_numbers.svg.png