Hi Peter, thank you very much for playing! I can see why you think it's a bug, and truth be told, I really tried to implement it so a x4 twice would be a x16 multiplier, but I goofed and made it work more like this: the first x4 works properly and makes the next die played 4 times. Then the second x4 gets played (4 times), so it becomes a 4x4x4x4 multiplier, which is indeed a 'bit' overtuned. I've now fixed this so it becomes a x16.