On the Subject of Marmite

...but Pa might not.

Press the Marmite every time the number of non-ignored solved modules is prime. Pressing on a non-prime or failing to press on a prime will cause a strike; you do not have to correct your actions on a strike.

Once all non-ignored modules are solved, press the Marmite to solve the module.

If there are several Marmites on the same bomb, each will display a number between 0 and (# of Marmites − 1), which should be added to the number of non-ignored solved modules before checking their primality. For example, an offset of +3 would require 4 to be treated as 7 (and thus, prime) but 5 as 8 (thus, not prime).