This is a challenge I found on anarcy golf. The purpose is to make an octagon out of the numbers 1 - 8:
11111111
1222222221
123333333321
12344444444321
1234555555554321
123456666666654321
12345677777777654321
1234567888888887654321
1234567888888887654321
1234567888888887654321
1234567888888887654321
1234567888888887654321
1234567888888887654321
1234567888888887654321
1234567888888887654321
12345677777777654321
123456666666654321
1234555555554321
12344444444321
123333333321
1222222221
11111111