The first known Square-2 was built by David Litwin in about 1995. He built three samples and capped them with thin grey plastic. Since then a number have been built by different authors independently (Jake, 2003, Noda, 2003, many in 2008), at least one other (Noda) choosing the "Square-2" name. See the links below to learn more about the puzzle's history in the forum.
In 2012 hknowstore started selling a mass produced version. Edge length: 55 mm Weight: 100 grams
Links
Forum Thread about updating the stickers on the first few (DLitwin, 1995).
Forum First mentioning of this concept in the forum.
Forum Thread about finally finishing the third of that set
Contributors
Thank you to the following people for their assistance in helping collect the information on this page: David Litwin.
Collections
This puzzle can be found in collections of these members: