0.1 - 0.9 numbers in mm heights

Quick test I made to check my z-height and ability of my printer to print at 0.1mm.
If any numbers dont show your nozzle is dragging the bed, and you can raise the bed by the highest missing number (be careful that you don't clog the nozzle).
If the numbers are messy, you're too far from the bed and need to lower it a little.