Hello,

I have been thinking recently and thought that shells mechanism puzzles were pretty much exclusively 3d printed puzzles. I recently realized however, that there are more of these type of mechanisms mass produced than I thought.

I was hoping we could get a list of all mass produced puzzles using this mechanism type, just out of curiosity's sake.

Pyraminx Crystal
Starminx II (face turning)
Rex cube/ Master skewb/ FTO (all have a dino cube for a core)
Rubik's brand 5x5
Dogic
Eastsheen/rubiks/lanlan/V --> 2x2
Dayan Mf8 4x4 ?

Anything else that I am missing? anything else anyone thinks may come about soon?

I'm not extremely familiar with shells mech but don't some 4x4s use it? Like the Dayan + MF8 one.

Well, the crazy 4x4 series might count... someone correct me if I'm wrong though.. There is a 3x3x3 "cube" hiding inside it I think.

Well, in that case, isn't every Eastsheen mech 2x2 (Lanlan, Maru, etc.) a shells mech puzzle?

I guess it just depends on how you define shells... I'm certainly not the best person to define that though...

I only say Dayan + MF8 because it has a 2x2 ball core (which does have a 3x3 inside but I wasn't sure if that counted)
Although now that I think about it, it's actually more of a cross 2x2 with added edges and corners.

I agree. To me the shell much is any puzzle which has been built up from layers of concentric spheres. Your plan Jane 3x3x3 can be built this way but you just need a single sphere so maybe it shouldn't be called shells (plural) in this case. A 3x3x3 built on a shell mech just has the slice layers much thinner inside the sphere then outside it. I can't say for sure if any mass produced 3x3x3 uses this exact mech or not but the basic idea is essentially the same. So are you trying to limit this to puzzles which require the use of 2 or more concentric spherical cuts? It looks to me like its being used to describe any puzzle which has a core which is another puzzle.

Carl

I'm not a designer or an expert at all in this area but to me the shells mech:

1) Uses concentric spheres.
2) All volume is filled by pieces (if there are "bubbles" it is because those pieces weren't needed and were deleted).
3) Is defined by a 2D sketch that defines the circles and other cuts that are revolved to generate the spheres and shapes of the pieces.

It just so happens that to get the cuts of the outer portion of the puzzle rather deep cut you might need to have inner pieces cut out of an inner spherical shell that hold those outer pieces in place and those inner pieces correspond to the pieces of a shallower-cut version of the puzzle.

*sigh*

It seems that so many things dealing with puzzles are very hard to define.

Despite what the shells mech may or may not actually be defined as, when I think of the shells mech I think

Consists of 2 or more concentric circles building up a "deeper cut" puzzle generally resulting in other common puzzles being hidden inside the mechanism.

thats basically the simplest way I can think of it. I am not sure if this makes even layered puzzle part of this or not.

Rubik's brand 5x5
Dogic
Eastsheen/rubiks/lanlan/V --> 2x2

The Rubik's and ES 5x5x5 are cylindrical, not spherical in their mechanism. Although perhaps built of nested cylinders, that isn't what is commonly considered the shells mechanism (spherical).

Dave

If I'm not mistaken, the dioctipoid (hoping I didn't mutilate the spelling) is shell-based.