Ok, managed to get a really nice one down:
$ratiov = $h/$w;
$uv = [$u, $v*$ratiov, 0];
$size = 15; # 0,30;
$outlines = 10; #1, 20;
$color1 = [0,0,0];
$color2 = [1,1,1];
$point = pvoronoi($size*$uv,4,0,.2);
#circle determining part
$dist = ($uv*$size)-$point;
$dotproduct = dot(dist, dist) * 4;
#filling the circles
$fac = fmod(sin($dotproduct*$outlines) , 1);
$color = ccurve($fac,0,$color1,4,1,$color2,4);
$color
This one is very similar to an old hand-drawn graphical pattern where you place a circle, and then another circle and you then draw circles around those. The problem with getting a computer to do this is that it’s a little hard to explain what exactly what you want, which makes things like having variation between circles while keeping the outline consistent a little hard.
EDIT: I updated it so the circles would be round…