(Square-wave shape)
G20 G90 G61
G0 X0 Y0 Z0
X-1
G64
G1 X1 F9999
X2 Y1
Y0
X3 Y1
Y0
X4 Y1
Y0
X5 Y1
Y0
X6 Y1
Y0
G0 Z1
X0 Y0
Z0
M2
%