Calibron Twelve Block PuzzleBackground (Extract by George Miller and Nick Baxter G4G12 Atlanta, 2016 article)
"This story starts in 1933 when the manufacturing company
Calibron, run by Theodore Edison, youngest son of Thomas Edison, published a Bakelite puzzle named
Calibron Twelve Block Puzzle.
As we will find out, this was a subtle and well thought out puzzle used
in a marketing effort to spread the name of Calibron. It was presented
in a rectangular box with 12 red pieces and one black spacer piece. The
challenge was to arrange the 12 red pieces into a solid rectangle of
unspecified dimensions. There is only one way to do this and it is very
difficult."
The puzzle is complete. This edition does not include the black spacer.
Interesting puzzle, almost 90 years old and in excellent condition. Very interesting for lovers of put together puzzles.