Hendecagon of a regular hendecagon is still impossible even with the usage of an angle trisector. It can, however, be constructed via neusis construction and also via two-fold origami. Close approximations to the regular hendecagon can be constructed, however. For instance, the ancient Greek mathematicians approximated the side length of a hendecagon inscribed in a unit circle as being 14/25 units long. The following construction description is given by T. Drummond from 1800: On a unit circle: The "regular hendecagon" has Dih symmetry, order 22. Since 11 is a prime number there is one subgroup with dihedral symmetry: Dih, and 2
How many angels can dance on the head of a pin? about how many could perch at the same time on the head of a pin"". Dorothy L. Sayers argued that the question was "simply a debating exercise" and that the answer "usually adjudged correct" was stated as, "Angels are pure intelligences, not material, but limited, so that they have location in space, but not extension." Sayers compares the question to that of how many people's thoughts can be concentrated upon a particular pin at the same time. She concludes that infinitely many angels can be located on the head of a pin, since they do not occupy any space there: