Rashkey 3Third of a series of three similar puzzles. The three differ only by the colors of the pieces.
ReciprocatorTwo sets of parallel plungers are also connected by an inner pinion. Pressing one plunger causes the adjacent plunger to move in the opposite direction.
Rhombus-Tri SliderA sliding piece puzzle similar to Elemental:Argon but with three plungers instead of four and some other small changes.
RigelTwo intersecting circles but with two concentric circles of pieces per half.
RootingerTwo intersecting circles combined with a plunger.
RotabramThree intersecting circles with gears. Pieces can be exchanged on two are rotated in each turn.
Rotascope - EscherFour customized Rotascope with themes based on famous works of M.C. Escher.
Rotascope - Escher IICustomized Rotascope with a theme based on famous works of M.C. Escher. This time with a non-circular body.