Message #1176

From: Andrey <andreyastrelin@yahoo.com>
Subject: Tetrahedral prism {3,3}x{}, 3 layers solved
Date: Tue, 28 Sep 2010 14:41:16 -0000

It’s strange that one of the smallest 4D puzzles is not listed inMC4D puzzle list, so you have to generate it by "Invent my own" command (with line "{3,3}x{} 3").
It took some time to find the most convenient views of the puzzle (view with two tetrahedrons has very different "shrink face" value than view with 4 prisms). You can’t rotate prism to 120 deg, so use sequence of two 180-deg turns instead. Not very easy…
I started with sorting of pieces - top, middle and lower layers (like the solver who plays with 3^3 first time - build one single-color face :) ). Then there was orientation of middle layer pieces and then combining of 3rd layers parallel to prisms (just 3-cubie segments) with adjacent cubies. Next step was to put all corners in their place - and there were first two problems.
First, middle layer was upside-down - and I had to flip all its pieces and save colors of top and bottom faces.
Second, in the end of this stage I found one corner piece (pair of pieces, really) with wrong orientation! It is normal for pyraminx, but here you have to think how it can be :)
When all corners ans 3Cs of middle layer were in place I found myself with 3 parallel pyraminxs and with the task to put all their 2Cs in place.
One operation was enough for it… well, almost enough. At first I tried to move cubies to places in proper orientation, but soon found that I can’t remember setup twists that contain of pairs of prism flips… So I decided to position pieces first.
Solving of 3 pyraminxs with the same sequence of 3-cycles went smoothly… until there were two transpositions on opposite faces (parity problem?). When I solved it there was one wrong oriented cubie on top side (and 3 on bottom) - but this time I could remember setup twist ))) So when I twisted 3 sets of 2 cubies, puzzle was almost solved.
So this one is solvable from the scratch, without operations development. It doesn’t beat {3}x{3},3 :)

Andrey