To create noise within the machine a fourth element is added to alter the movement of the three pendulums. This addition is a bed for the table that rotates in two axis that can be fixed at an angle. This alteration should effect the drawing making it less predictable as a sine motion.
The joints under the table display a similar build to that as guards on sanding machines in the wood-shop. They function in a similar manner, having two channels,one for fixing them at the right angle and the other a slot for guiding the plane into that angle.