Message #1958

From: Andrey <andreyastrelin@yahoo.com>
Subject: IRP {4,6} VT solved
Date: Tue, 13 Dec 2011 12:34:23 -0000

Hi all,
today I tried to solve {4,6} (12 colors, vertex-turning) in IRP mode. It was hard enough. One twist touches about 1/3 of puzzle pieces (almost as in 3^3), and at the first glance, two intersecting circles have two areas of intersection. But some investigation revealed that actually number of elements in this puzzle is not 92 (as expected), but only 50: all non-vertex pieces are grouped in rigid pairs of elements symmetric with respect to any vertex (in surface geometry). For example, what we see as central grey central element is actually a half of grey-light_blue 2C piece. Edge elements are actually 4C, and petal elements are also grouped in pairs - but again, grey color is grouped only with light blue. So we can swap these elements… but not every pair of them - there are two orbits of petal stickers. I noticed it too late and spent some time trying to find setup moves that are actually impossible.
Result is 517 twists. It was only 25-twist scramble, but I didn’t see any shortcuts, so it was like full-scrambled for me.

Andrey