commands:
G0 Xx Yy - Rapid move to (z,y) coordinates
G1 Xx Yy - Move to (x,y) coordinates
G4 Pn - Wait n ms
M300 S10 - Pen down
M300 S50 - Pen up
Tn - change to nth tool
G28 - Home
G90 - Set to absolute positioning
G91 - Set to relative positioning
M2 - Program end
M17 - Enable steppers
M18 - Disable steppers
M80 - ATX power on
M81 - ATX power off
M112 - Emergency stop
M114 - Get current position
M703 - Get info from printer firmware
M118 OK - Response to host when line done
; - line comment
(...) - block comment