Drawing of models demonstrating self-reproducing mechanisms

Paper drawing of models demonstrating self-reproducing mechanisms in chemistry and biochemistry, made by Lionel Sharples Penrose, mid 20th century

The writing is faded, but the puzzle appears to require the user to ‘Move from position A to position B in 9 moves and go back again.’ It is a sliding block puzzle similar in type to the ‘15’ puzzle where 15 squares are moved around a 4 x 4 square board so the numbers are in order. This type of puzzle has been popular since the late 19th century.

There is a story related by Oliver Penrose, one of Lionel’s sons, that when he brought his future wife Joan to meet the family in 1953, Lionel thrust a puzzle into her hands saying ‘see if you can take that to pieces’. This is one of several interlocking cubes Lionel made.