Perhaps this is already well known but it surprised me. I bought some "Magic Cubes" from my local Walgreens here in Illinois to experiment on. They come in a two pack of a regular size and a mini cube both with glitter foil stickers. The first thing I noticed was that the supplied "Magic Cube Solution Diagram" is exactly the same as the one supplied with my Meffert's Assembly Cube (except it doesn't have the black and white how to take it apart directions on the back). Then after I removed the stickers and revealed the center cubes I found the familiar pop out tile. So I got out my Assembly Cube "Key" and popped the cube apart to find the exact same mechanism as the Assembly Cube I have on my shelf. The plastic isn't as nice as the Meffert's version but it's nice to play with. I wonder if Meffert's is the source of the Pyramorphix clones that have recently shown up at dollar stores.

That's where I find them. There are also tiled ones of AWFUL quality.

FYI