{ RCSid $Id: basin.cal,v 1.1 2019/01/08 23:53:04 greg Exp $ }
{
	basin.cal - calculate coordinates for basin sink.
}

sq(x) : x*x;

R(t,p) : 5 + (3.25*sq(cos(p))+1.75*sq(sin(p))+1*sin(p)*sq(cos(t)))*sq(sin(t));

x(t,p) : R(t,p)*sin(t)*cos(p);
y(t,p) : R(t,p)*sin(t)*sin(p);
z(t,p) : R(t,p)*cos(t);

theta(s) : PI*(.5+.5*s);
phi(t) : 2*PI*t;