If Rubik had been working in two dimensions instead of three,
he might have come up with this instead of his cube.
You start with a mixed up grid of numbers in different colors.
The goal is to get 1-5 of the same color in order in each row.
You can also try to get 1-5 of the same color in order in each column.
You rearrange the numbers by swapping horizontal groups.
First decide whether you will use groups of two or three
The same size is used throughout one puzzle.
With two, the task is considerably easier than with three.
Click "New puzzle" to get a new grid or change move size.
To swap two groups (which cannot overlap or extend beyond
the edges), click on the left-most member of each group.
After the second click, they change places.
The mathematics of this game is similar to both
the 15 Puzzle (Google results) and Rubik's cube.
In terms of complexity, it is much closer to the former
than the latter, nevertheless it is a very rich permutation group
(for the mathematically inclined).