In geometry, the bicorn, also known as a cocked hat curve due to its resemblance to a bicorne, is a rational quartic curve defined by the equation[1] y 2 ( a 2 − x 2 ) = ( x 2 + 2 a y − a 2 ) 2 . {\displaystyle y^{2}\left(a^{2}-x^{2}\right)=\left(x^{2}+2ay-a^{2}\right)^{2}.} It has two cusps and is symmetric about the y-axis.[2]