Orange plate performs planar motion without rotation. Its upper surface is kept always horizontal thanks to 4 bevel gear drive of equal tooth numbers driven by brown spur gear. Sliding joints between green and yellow bars and between blue and grey shafts allow radial displacements of the orange plate. Pink gear is fixed.
Change of popcorn fixed cam profile gives various trajectories of a point on the orange plate.
4 bevel gear drive can be replaced by 4 screw gear drive in another embodiment of this mechanism.