Question 379

Geometrically, the 'X' shape can be regarded as (the area inside of) an irregular icosagon or 20-sided polygon. The proportions of were fixed based on a 5x5 diagonal grid.
Characteristic is the 90° rotational symmetry (that is, the symmetry of the cyclic group C4h) and chirality, hence the absence of reflectional symmetry, and the existence of two versions of 'X' that are each other's mirror image.
The mirror-image forms are often described as:
clockwise and counterclockwise;
left-facing and right-facing;
left-hand and right-hand.
An explanation for 'X' origin is suggested by Carl Sagan in his book Comet, proposing that the symbol was inspired by a comet approaching Earth closely enough that the jets of gas streaming from it, bent by the comet's rotation, became visible. This explanation has found some adherents among catastrophists. What is 'X'?

Answer: The Swastika. Cracked by Johny Walker, Aditya Datar, Navin Pai, Satya, Rohit and Pushkar.