This is a design to help you figure out the correct probe offsets for your specific BLTouch / CRTouch mounts. The lines on the design should be 5mm apart, but it doesn't really matter because it's mostly just to be able to make sure you can measure straight with your ruler.
Basically the instructions are:
1. Tape the tool to a corner or side of the bed so that it's perfectly even. (Pick which ever corner based on where your probe is mounted.)
2. Move the probe so that it is just directly above the small circle in the corner. (I'll usually have to deploy the probe in order to see it.. Just make sure to stow it back afterwards.)
3. Heat up the nozzle to whatever temp you need to melt the plastic.
4. Lower the nozzle just enough to melt the plastic and be able to see where the probe is.
5. Raise up the nozzle.
6. Measure with a ruler to find the exact Probe location!
I didn't know of anyone else that has done this, but I think it's very useful to get accurate probe offsets.
The author marked this model as their own original creation.