A “Domino Reduction” Solve by Sebastiano Tronto

Scramble: B2 L2 B2 L’ B2 L F2 D2 R2 D L2 D’ B2 R2 B2 F’ L2 R2
Solution: R2 L2 F’ U’ R2 U L’ D2 L D2 L’ D L D’ F2 U’ L2 D L2 D’ B2 R2 D’ R2 B2 L2 B2 (27 HTM)

 

Explanation:
Premove:
B2
R2 L2 F’ //EO (3/3)
U’ R2 U //Blocks (3/6)
L’ D2 L D2 L’ D L //Domino Reduction (7/13)
D’ F2 L2 //More Blocks (3/16)
L2 U’ L2 D L2 D’ * L2 U //Pairs Commutator, 1 moves cancel (6/22)
B2 //Undo Premove (1/23)

At this point I began looking for places to insert those nasty edges cycles like R2 B2 L2 U L2 B2 R2 D; the best I could find was a 2-moves cancellation for a 29 total. With some hint from IF (I’ve looked at where to insert the cycle):

* = B2 R2 D’ R2 B2 L2 U’ L2 //Edges 3-cycle, 4 moves cancel (4/27)

Comment:
I randomly decided to try EO first and since it led to a good blockbuilding continuation (first six moves) I explored it a bit. I have then decided to for a further reduction (EO can be seen as reduction to <U, D, R, L, F2, B2>, and Domino Reduction leaves you in <U, D, R2, L2, F2, B2>).

Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>