Why Does The Laserbot Cut Or Engrave The Image In Different Size On X Axis (Or Y Axis) - Makeblock mBot Manual

Why does the LaserBot cut or engrave the image in different
size on X axis (or Y axis)
If the LaserBot cuts or engraves the image in different size on X axis (or Y axis) as the picture
shown below (the image's Y axis is stretched), here are troubleshooting you could try.
Update firmware.
1.
Swap the two motor drivers' position on Mega Pi and check if the image's X axis is stretched
2.
(like the second picture below).
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