Quelklef/prime-spirals
https://math.stackexchange.com/questions/2072308/help-with-a-prime-number-spiral-which-turns-90-degrees-at-each-prime/2076349#2076349
JavaScript
https://math.stackexchange.com/questions/2072308/help-with-a-prime-number-spiral-which-turns-90-degrees-at-each-prime/2076349#2076349
JavaScript