First published in the "Mathematical Games" column in Scientific American magazine way back in 1979, the Four Glasses Puzzle continues to stump even the greatest minds. Using logic skills and mathematical thinking, this word puzzle is meant to improve your reasoning in a fun, challenging way.
The puzzle is also known as the “Blind Bartender’s Problem” because it envisions a fictional bartender. Four glasses are placed on each corner of a square lazy Susan, with some turned upright and some upside down. A blindfolded bartender is then asked to rearrange the glasses so that they are either all facing up or all upside down. The lazy Susan is rotated over and over again, and the same bartender is allowed to feel only two of the glasses after each rotation to determine which to flip over in order to ensure that they are all facing the same way after a finite number of turns. Once they are all facing the same way, a bell rings.
Can you develop an algorithm to ensure that the bell rings after five turns? Check your answer here!
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