Why Square Corners - COmmon Cube Questions

(Transcript from video)

This is the first in a series I’m calling Common Cube Questions.

These will be short videos explaining some simple questions that come up within the cubing community, and will be geared towards those that are getting into cubing although I hope they will be helpful no matter what your experience is.

This first video is on square corner pieces on cube.  Most cubes that are coming out now have what are called florian cuts in the pieces of the cube to help them perform better, but there are some out there like the Gans 357, and the Cong’s Design YueYing that have more squared corners.  When I first saw this I was first confused as to why we were taking a step back in design until I found that they didn’t lock up like expected.  So how does it work.

First lets take a look at an original Rubik’s cube which I restickered.  I will explain these stickers in a later video.  The pieces are very square and although it can corner cut a bit, reverse corner-cutting is non existent.  You can see that even the smallest amount wont move.

Original Rubik's Cube

Here I have a DaYan Zhanchi and a MoYu AoLong V1.  Both have the curved pieces that allow it to still corner cut but makes reverse corner-cutting a breeze.  The pieces just slide off of each other without any major locking happening.  

Now moving onto the Gans 357 we have these square corners.  Again it can corner cut well, but it still reverse corner cuts amazingly well, I would say more than the Zhanchi or AoLong.  Now I just assumed the insane curve of the center pieces allowed this to happen, but lets take a look at the Cong’s YueYing.  The square corner pieces might be a bit harder to see because it is a black cube, and the stickers are curved.  This does not have an extremely rounded center pieces and still reverse corner cuts at least have a piece.

So what is going on to allow this?  Lets take a look at the corner pieces of the Gans and the YueYing.  Although they look square from the outside, behind the sticker they are shaped a bit differently.  The Gans puzzle has more of a cone, or umbrella shape, and the YueYing has holes in the sides of the pieces.

YueYing Corner on left and Rubik's corner on right

When we see it in action you will notice that the corner pieces actually comes over top off the center pieces when reverse corner-cutting.  The space cut out of the corner pieces makes a perfect area for the center to slide into allowing the cube to flex a bit more and making it possible to reverse corner cut.  

Ok, so we see how it works, but what is the point of it?  If we take a look at the AoLong which has very large Florian cuts in the pieces the pieces itself can very easily twist in its place.  This was my main for a long time, but I became so frustrated with corners twisting during a solve that I finally had to put it down.  The sharper edges on the Gans and YueYing greatly prevent a corner from twisting.  You might be able to do it on purpose, but it is next to impossible to twist a corner during a solve.  

There are some cubes like the new MoYu HuaLong that has corner pieces in between the two styles.  The corners are not completely squared off, but have less of a curve than the other pieces.  It also incorporates the umbrella like design of the Gans as well as the holes of the YueYing.

Thank you for watching.  If you have any suggestions for other Common Cube Question videos please leave them in the comments below.