Need help with Macro's for Open-Ended Rolls

I'm having a lot of troubled getting through the Macro Wiki for roll20 to find the specific way to create a macro that does the following: A D12 is rolled, and the character may reroll every 12 that comes up with a +4 cummulative modifier. So, if the reroll comes up a 12 the second time a +8 is added, and if it comes up 12 a third time +12 is added, etc. On the other hand, every 1 that comes up is rerolled with a -4 cummulative modifier. So, if the reroll comes up a 1 the second time a -8 is added, and if it comes up 1 a third time a -12 is added, etc.

Can't get a cumulative modifier. It's only going to re-roll the dice.

Not sure it would be better than having to reroll every time, but you could sort of work around this through Ability Command Buttons and roll queries. At the very least, it would do the math for you. Your macro would look like this at its most basic: D12-Roll: [[1d12 + ?{Number of 12's|0}*4-?{Number of 1's|0}*4]] [Rollagain](~selected|D12-Roll) So the first time you roll, you would just leave the default 0 in the two roll query prompts giving you a base 1d12 roll. If a 1 or a 12 is rolled, you click the button in chat to roll again and it asks you how many 12's/1's you've had and automatically adds/subtracts the appropriate multiple of 4. You could also of course do this without the ability command button and just click the token action or macro bar button for your macro each time you need to reroll.

thx - i'll give it a spin. Here's hoping that Roll20 will add more Macro Options in the future.