XY Calibration Square - 100mm

**Calibrating X and Y axis on the Original Prusa i3 MK2, MK2.5 and MK3**

** UPDATE 26 October 2018 ** Modified step 11 to show the option to save changed values to firmware using M500 command.

** UPDATE 6 October 2018 ** Confirmed this process continues to work for the Prusa MK2.5 and Prusa MK3 printers. This process also works well for most other printers that use Marlin firmware.

** UPDATE 5 April 2017 ** Changed reference from M501 to M503. Note that Prusa Research i3 MK2 firmwa