Twisted heart

By Roger Bagula
Graphics by Paul Bourke

January 2003

x = ( |v| - |u| - |tanh(m u)/m| + |tanh(m v)/m| ) sin(v)

y = ( |v| + |u| - |tanh(m u)/m| - |tanh(m v)/m| ) cos(v)

z = m ( u² + v² ) / ( cosh(m u) cosh(m v) )

0 <= u <= pi, -pi <= v <= pi, and m = 1/sqrt(2)