Every time it triggers, it multiplies your current value of that color. So say you have 1k black from various other triggers that already happened that spin, and you land on a 9x multiply block. That block will increase your total black from 1k to 9k. If you trigger it twice, then the second trigger will take it from 9k to 81k and so on. It's how you end up with scientific notation scores. By having eye (5x triggers) land on a 9x block.