I think it is a joystick because in the Analog Four "The Demon Who Wears Me" short, Hector is covering something on the left side of the Analog Four at 5:20 and at 5:26 it looks like his left hand is manipulating something on the left side of the Analog Four as it effects the audio being heard, although I am sure the audio was not the result of his hand movements and it is highly likely the audio was recorded separately, maybe it is symbolically related
but there is definitely a mystery to be solved on the left side...ENHANCE around that tree...