This is a dice-roller app for use with Prophecy: A tabletop roleplaying game about fate and destiny. It implements the algorithm described in the rulebook for making a check to determine the outcome of a scene.
To make a check, the players roll a dice pool consisting of some number of six-sided dice. For every die that yields a 6, another die is added to the pool. Any die that yields a 4,5, or 6 is a hit. The result of a roll is the total number of hits.
To use this app, the players use the slider to specify the number of dice in the pool and then push the "Roll Dice" button. The app then simulates rolling those dice, adding any additional dice as required to account for any dice that yielded a 6, and displays the total number of hits that result.