The article is written in Japanese, but I thought the idea would be obvious enough from the picture (and the linked source code) even if you don't read Japanese. In case you are wondering, here is a translation.<p>----<p>11111111111122211111111111122622111111999992266211119999999222221119999999966666111999999999996611166622622266661162262262222266116226622222222611622662226222261662222266666661166662222666626111166222222226611111999966966661166666699696661166666666966966116666666699696111662266669966911162222669999621112222269992999111222229999999911121229999999991161229999999999166111999999999666611169999999966666669669999996666666999669999666666699999119966666669999911111111666999911111111166111111111111116111111111111111<p>is a 512-digit prime number. When fit in a 16 x 32 rectangle, it will be:<p><pre><code> 1111111111112221
1111111111122622
1111119999922662
1111999999922222
1119999999966666
1119999999999966
1116662262226666
1162262262222266
1162266222222226
1162266222622226
1662222266666661
1666622226666261
1116622222222661
1111999966966661
1666666996966611
6666666696696611
6666666699696111
6622666699669111
6222266999962111
2222269992999111
2222299999999111
2122999999999116
1229999999999166
1119999999996666
1116999999996666
6669669999996666
6669996699996666
6669999911996666
6669999911111111
6669999111111111
6611111111111111
6111111111111111
</code></pre>
which can be colored: (Super Mario appears)