Using a stepper motor with a 3D printed attachment (see below) to make the blind turn. The Arduino is programmed to make the motor turn 9 rotations and then pause for 2 seconds before reversing the other way to complete another 9 rotations.It does this on a loop until you switch it off at the plug. The blind dips into a trough filled with paint and then smears it up the surface of the canvas as it travels up and down.