This app works, producing random rolls for the seven dice required to play Formula D/De. However its graphics and ease of use are a bit rough around the edges. The only reason I gave it a third star is because it EXISTS and is the only dice app of its kind for Formula D/De. Though it is functional, the following comments are more than enough reason to rate this app at 2 stars at best:
The gear names of each of the dice run out of their frames and aren't able to be read so you have to be familiar with the game to remember which die represents which gear. It would also be REALLY nice if when you selected a die it was highlighted somehow so you could quickly see which one you are rolling/which one was just rolled. Probably the biggest frustration is the lack of visual (and sound perhaps) to let the user know the roll button was successfully pushed. This is particularly problematic when the same number is rolled two or more times in a row (which is statistically common with the two lowest "gear" dice). There is no flash, no flicker, no animation of any kind on the shown number at ALL to let the user know a roll of the exact same number has occurred; the shown number simply sits there. It's difficult to know if a second "4" was rolled or if this is the "4" rolled previously.
Formula D/De being an uncommon game, I can see that there is absolutely no pressure to improve this app in any way. I only used it because I was traveling and purchased an expansion board for Formula D/De and using found items and this app I was able to play the game without all the other base game pieces. That said, I could easily find a place for this app at the game table every time we play Formula D/De if the above improvements were made.