Originally posted by atomicbob1 at that ‘other site’

This is a neat idea that I’m going to try out with my family tonight. He used it as a minigame in a kids RPG, but I think it’d be an easy standalone as well. Scroll down to the picture of the dice for an explanation.

https://www.penny-arcade.com/news/post/2019/06/03/dd-as-a-tool

Relevant portion:

I used 9 d10 and lined them up with the top numbers showing 1-9. These dice represent the gems down in a chest deep below the surface of the ocean.

Two players stay up on the boat to pump air down to the player trying to get the gems. In my game of three players this worked great. The two players on the boat each roll 1 d6 and pass it down to the player in the diving suit. This represents their air and they can keep getting gems only as long as their air lasts. Each time they get handed two d6 they must look at the sum and try and remove a number of gems whose face up numbers equal that sum. For example if the players on the boat pass down a 4 and a 3, the diver has 7 to work with. They could take one gem with a seven face up or they might take the 5 gem and the 2 gem. When they can no longer retrieve any gems they are out of air and have to return to the surface with the treasure they collected.