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I worked out that there are 512 solutions for worms....
I know this because there are 8 different ways that each worm can be positioned and there are 4 different worms, and 8 x 4 is 32.Then you must times 32 by 16 as there are 16 places that the worm head could start at, so there are 512 solutions.

I also worked out the smallest and the largest possible combination that the worm could possibly lie on here is what I worked out...

For the smallest the head must start on 34 and go strait up so it would go , 34, 24, 14 and then 4 so the total would be:76

For the largest combonation you would have to start on 67 and go strait down so it would go , 67, 77, 87 and then 97 so the total would be : 328