You can read the code, figure out what primitives you have, translate the problem into something simple (I like card and board games), then map it back.

Problem: two processes each do this ten times: - read the counter - do any number of other things in other processes - write back what you read, plus one.

Game: You have two piles of cards. Each card costs 1 move to play, but lets you discard any number of cards from other piles at the same time.

Solution: play one red card, discarding everything but one blue card. Play the single remaining blue card, discarding the leftover red cards.

Back: process 1 reads, process 2 runs 9 steps, process 1 writes, process 2 reads, process 1 finishes, process 2 writes.