Compass and Straightedge
Compass and straightedge
Number 866
Date Feb. 28th 2011
Previous Nanobots
Next Herpetology

Compass and Straightedge is the 866th xkcd comic.


The compass and the straightedge are the classical tools of Geometry. While the work of Greek mathematicians 2,000 years ago was very impressive for its time, they lacked the methods to determine which problems were unsolvable using their system. For the most part, they flatly rejected the possibility of such problems being unsolvable. However, since then, the following famous "elusive" problems have been proved to be impossible (with a finite number of steps):

This doesn't stop people trying, even today. The joke is that the reader expects one of these three names to finish the sentence.

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"The Greeks long suspected this, but it wasn't until April 12th of 1882 that Ferdinand von Lindemann conclusively proved it when he constructed himself the most awesome birthday party possible and nobody showed up."

See alsoEdit

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