Michael Schumacher’s scientific contributions

... Motion is defined as changing the position of a rigid element in space [19]. Schumacher et al. claim it can be reduced to three basic types: "rotation, translation, or the combination of the two" [20]. Moloney provides straightforward and clear definitions: "translation describes the movement of a component in a consistent planar direction; rotation allows movement of an object around any axis" [21]. ...

Reference:

A Systematic Review of the Most Recent Concepts in Kinetic Shading Systems with a Focus on Biomimetics: A Motion/Deformation Analysis