The top shelf of my dishwasher started to misbehave (would not stay straight). Upon investigation, turns out that the rollers in the rail that supports the shelf were coming off the metal shafts that were supposed to hold them. A little more digging and I found a C-clip of sorts on the bottom of the dishwasher. Turns out that C-clip retains the rollers on the metal shafts. The problem is that the C-clip became too thin and the little detent on the roller that is meant to keep it from sliding out, could no longer hold it.
The replacement C-clip can be purchases for around $4 per piece plus shipping. It bothered me to pay $20 for, cumulatively, about a gram of plastic. Besides, this situation is exactly what 3D printers are for. So I designed and printed the clips myself, and thought that I should share the design with others.