Message #3967

Subject: My physical 2^4 solution
Date: Wed, 17 Jan 2018 22:18:34 +0000

My physical puzzle finally came today, and when I started to try to figure out a solution, I was surprised at how easily it came together. I just got a 2:54.52 single, which (correct me if I’m wrong) I think is the first sub-3, and the method isn’t even fully optimised, so I thought I should share my method with the group.

To be clear up front, I have been using Strict ROIL, RKT (which is in ROIL, but useful to point out), and Michael’s physical algorithm for doing I twists, generalised to allow quick access to any twist of the puzzle.

First, I begin with the puzzle held left-right, and i place opposite colours on the D-cell, much like the 2^3 guimond method. This is achieved fully intuitively, although RKT is recommended for a lot of the cases.

Then, I orient the U cell pieces using RKT OLLs. An important process in this step is using Michael’s algorithm Iy’ Rx2 iz Rx2 Iy/Iy’ Rx2 Iz’ Iy, which effectively does an IU/IU’ twist, depending on the centre move. (Here y is the vertical axis, to clear up any confusion). You can bring any cell to the centre using R/L rotations to make any twist on any cell. This can bring corners from the outside R/L cells onto the F, B, I and O cells, at which point you can use RKT on the R/L cell to orient pieces. I have no algorithm for a singe corner twist, because if you are smart with your set-up moves, it is unnecessary.

I then use the ROIL FOro of Iy Oy’ Rx2 Bz2 Uy2 Rx2 to place those oriented cells on the outside corners, and then turn the puzzle up-down.

At this point, I solve the pieces of the new D cell similarly to a cuboid, using R2 U R2 U’ R2 and U* twists to pair and place corners. This can be done in any order, and I would recommend experimenting yourself, as it will make your solves much faster if you can intuit this step, rather than doing it algorithmically.

You are then left with a single corner twist free RKT last cell, which you should all be familiar with.

Apologies for anything that isn’t clear in this description. The solve is mostly intuitive, and so it’s difficult to concretely describe what I’m doing in each step. If it would help, I could record a video of my solution, although it might have to wait a while.