Contains

• puzzle

  A particularly baffling problem that is said to have a correct solution; "he loved to solve...

• pons asinorum

  A problem that severely tests the ability of an inexperienced person.

• rebus

  A puzzle where you decode a message consisting of pictures representing syllables and wor...

• case

  A problem requiring investigation; "Perry Mason solved the case of the missing heir".

• homework problem

  A problem that students are assigned to do outside of class.

• riddle

  A difficult problem.

• sticker

  A particularly difficult or baffling question or problem.

• Gordian knot

  Any very difficult problem; insoluble in its own terms.

• koan

  A paradoxical anecdote or a riddle that has no solution; used in Zen Buddhism to show the inadequacy...