I created a similar dice mechanic for my d8-based home-brew game system that I plan to play-test here on Roll20. The difference being that dice are not added together when rolled. Instead dice are rolled to beat a target number to accumulate successes. So if a character's dice pool included 3 dice (say d8's since my game is d8-based) and the target number was 7, any 7's or 8's rolled would count as successes. However, there are two alterations to the basic mechanic. The first is "revolving dice" which work like exploding dice in other games. When a die shows its maximum value, a success is tallied and the die is rolled again; tallying successes and re-rolling as long as the die continues to roll its maximum value. That function is covered by basic syntax in the Roll20 dice roller. No real issues there. The second alternate mechanic is my game's version of "exploding dice", which are similar to Marcus V.'s mechanic that opened this thread, only using successes rather than mathematical sums. An exploding d8 in my game that rolls an 8 tallies one success, and is then rolled again along with a second d8. If both those d8's roll 8, the player would tally two more successes and roll 4d8, and so on (and if only one of those dice rolled an 8, the result would be one additional success and another re-roll of 2d8). Make sense? Btw, I am also new to the API (became a mentor last month, half of which I spent in the hospital) and relatively new to coding, aside from basic HTML and a little CSS. This week I have been coding character sheets and am just now learning the syntax for macros, etc.