Skewb

Code for drawing, manipulating, and finding the shortest solution for a skewb.

Terminology

To turn the skewb around a corner means actually rearranging the pieces. To rotate a skewb is just to look at it from a different angle without changing the state.

The skewb has eight corner pieces. If you disassemble a real skewb, you will find that four of these are fixed to the inner mechanism while the other four are floating and are not attached to anything.

A normalized skewb has been rotated so that it is in the canonical position. The canonical position is when the yellow-orange-green corner piece is in the upper back left position and the yellow-red-blue corner piece is in the upper front right position. This rotation is always possible since these are both fixed corners. Normalization makes comparing skewbs for equality up to rotation easier.

Future work

• The skewb has a small enough state space that it would be feasible to cache the shortest solution for every state.
• When converting a Skewb to a NormalizedSkewb, automatically rotate the Skewb to the canonical position. Currently, normalization fails if the skewb is not already in the canonical position.
• Remove the even_rotation field from Skewb because it is redundant. We can compute it from the corner positions.