In terminology, puzzle, from pusle ‘bewilder, confound” (1590s), of unknown origin (1582), possibly frequentative of pose in obsolete sense of ‘confuse, perplex’, is a question, problem, and or contrivance that interrogates the mind, resulting to test one’s ingenuity; similar to conundrum and or riddle. [1]

Quotes
The following are related quotes:

“In 1809, Goethe published a book which was a puzzle both to his admirers and his enemies. This was Elective Affinities.
Hjalmar Boyesen (1885), Goethean scholar

“I have run my head hard up against a form of mathematics that grinds my brains out. I flounder like a sculpin in the mud. It is called the ‘law of phases’, and was invented at Yale [by Gibbs]. No one shall persuade me that I am not a phase. On the physico-chemical law of development and dynamics, our society has reached what is called the critical point where it is near a new phase or equilibrium. My essay ‘The Rule of Phase Applied to History’ is a ‘mere intellectual plaything, like a puzzle’. I am interested in getting it into the hands of a ‘scientific, physico-chemical proofreader’ [see: Henry Bumstead] and I am willing to pay ‘liberally for the job’.”
Henry Adams (1908-09), aggregate personal note communications [2]

See also
Modern queries
Reverse engineering puzzle

References
1. (a) Merriam-Webster Collegiate Dictionary, 2000.
(b) Puzzle – Online Etymology Dictionary.
2. Samuels, Ernest. (1989). Henry Adams (human molecule, pg. 115; physico-chemical, pgs. 401, 411; “Note to John Jameson”, pg. 409). Harvard University Press.

External links
Puzzle – Wikipedia.

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