Angled filler for bicycle seatpost lights

I've got a bunch of tail lights for my bikes, some are really nice (any of the [Bontrager lights](https://www.trekbikes.com/us/en_US/equipment/cycling-accessories/bike-lights/c/E312/) are really, really nice) and some are kinda cheap. The [nice lights](https://www.trekbikes.com/us/en_US/equipment/cycling-accessories/bike-lights/bike-rear-lights/bontrager-flare-r-rear-bike-light/p/13202/?colorCode=red) mount to the seatpost with an angle so that the light is shining parallel to the ground, which