After daylight savings ended, I was unable to bike anywhere after dinner since I didn't have a bike light. I looked for one online, but found that there was a harsh divide between cheap, dim bike lights, and bright yet expensive lights. However, I figured that I could strike a middle ground by making my own. 
I found a small 1000 lumen flashlight online that had a unique magnetic ring. I designed this 3D-printed mount that attaches to the light using four small neodymium magnets, and uses a recycled bike reflector mount to attach the flashlight mount to my bike. 
The final design is made of two durable PETG components glued together. Small ridges in the mount squeeze into the profile of the flashlight to ensure that the flashlight doesn't bounce out of the mount during bumpy rides.