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