A translation of a rounded Rubik's style 3-D puzzle.
Designed upon a round 8-colour columns' keychain version of the Rubik's style puzzle cube.

Another implementation, of mine, related to this puzzle genre is Missing Link, issued in 2002/04. Besides a series of square cube zrf's, a triangular Pyramid puzzle (implemented by Karl Scherer) is also available at ZillionsofGames.com.
* Included within RoundKeyCube.zrf are implementations of the 3-colour 'Diamond Cube' design. In physical form, the Diamond Cube was similar to the Pillow Cube.
* Per TwistyPuzzles.com, Rhombicuboctahededron's physical difference from Diamond Cube was that its (framed) 'MidSquares' tiles were the exact same size as its outer edge 'Squares'. On assumption, I've left its Win Condition to accept any square(s) to every outer OR middle position.

Object:
Rearrange the Pieces into columned sequences by colour.
Inter-connected columns and rows can be shifted up, down, sideways, and/or a 3x3 portion may be rotated. As with the physical 3-D 'wrap around' original of this puzzle, rotations are limited between corner pieces (here labelled CrnrOvals). Rotation moves are only accessed via the plain square pieces.
Win Conditions can be met with the matching pieces along any column, towards the left or right. (note: My suggested RoundKeyCube-cornered variant solution is incomplete.)
The pre-solved 'freeplay' variants within RoundKeyCube.zrf do NOT have a Win Condition attached.

Strategy:
(Mid-row destined) Squares which do NOT directly rotate, along with the Corner Ovals, have a frame outline.
Their four columns can instead be cycled through the singular top and bottom positions and conversely along into their opposite columns - as hinted by two thin background lines. Corner Ovals should only exist upon every other column of this puzzle.

A standard Rubik's cube has 12 columns around, with a top and bottom 3x3 grid. These 2-D puzzle variation displays contain 8 columns as each set of conjoined corner side columns are reduced into one. The top and bottom grids are likewise reshaped into only one central square each (drawn here as circles).