useage example: -vf 'scale=256:256,mp=geq=random(1)/hypot(X-cos(N*0.07)*W/2-W/2\,Y-sin(N*0.09)*H/2-H/2)^2*1000000*sin(N*0.02):128:128'
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>