In the 1940s Stanislav Ulam worked on the Manhatten project. Later on, and after a nervous breakdown at that, he was recruited to help out Teller with the implementation of the hydrogen bomb.
Ulam also had his recreations. He invented the Ulam spiral which takes the numbers 1,2,3 etc, and wraps them round a spiral. Then he marked the prime numbers, giving a strange looking grid style pattern.
ULAM 50
63 62 61 60 59 58 57 56
36 35 34 33 32 31 30 55
37 16 15 14 13 12 29 54
38 17 4 3 2 11 28 53
39 18 5 0 1 10 27 52
40 19 6 7 8 9 26 51
41 20 21 22 23 24 25 50
42 43 44 45 46 47 48 49
This is something you can put on your screen. It should be
titled something like 'GROUND ZERO' because it is easy to
fantasize that the image looks just like an impact site on a
city. Probably that would take several days on a 1950s computer,
but it can be done in seconds on any modern consumer product.