Spike Growth Macro

Hello, I hope everyone is doing well. I had an idea that I want to see can be done as a Macro but not sure how. Spike Growth: For every 5 feet the enemy moves through it, the target takes 2d4 damage. So, if we call every 5 feet a Step, then I am looking at (Step*2)d4 damage. Simple enough, but right now I am trying to process in my head how to script that down as a Macro. Any help?

YOu know what, I feel dumb.... I thought a logic wouldn't work right, tested it to actually DO work, and it was very easy to set up. &{template:simple} {{rname=Spike Growth}} {{r1=[[(?{Tiles Moved|1}*2)d4]]}} {{normal=1}} I don't know why I thought it would be difficult to set up, my bad...