Summary

Something silly and dumb for my ND miata. Put a 3mm bolt through the holes in the print and in your rear wind deflector, double side tape mount the arrow directly below the Miata and start measuring how much fun you're having by how far off the arrow the miata is swinging!
See it in action in this rear view shot.
You'll need some M3 washers, a nylock M3 nut, just the right length M3 bolt and probably some graphite lubricant for the most swing!