there should be an item called "7 8 9" which gives the number 7 the ability to eat the number 9 and add it's multiplier ability thing to the 7.

Pi is closer to 22/7 than it is to 3.14, so an additional 1 coin every 7 spins would be a good approach to GULL1V3R's idea.

Also, it could be 1 coin every 25 spins instead of 4 coins every 100 spins

spelling out 69 or 420 should give more coins

The pi symbol plus all of the adjency bonuses crashed my game I had a run that went to the moon as the all numbers bonus worked. I eventually got luck modifers so I had only numbers 5s 7s, 9s and multiples Pi on board if there were two or more Pi symbols with bronze gear, and protractor the game could not compute. After every spin and froze after a couple spins then crashed.

I like the idea that Gull1v3r suggested, it's not all that practical but neither is getting 0.14 per turn.

for implementing the .14 in Pi, you can add "Adds 1 every 10 turns. Adds 4 every 100 turns"