DD on http://evanw.github.io/csg.js/

gistfile1.txt

var count = 4;
var dist = 0.3;
var radius = 0.4;
var start = -(count*dist/2);
var last = CSG.sphere({ center: [start, start, 0], radius: radius });
for (var i = 1; i <= count; i++) {
  last = CSG.sphere({ center: [start + i*dist, start, 0], radius: radius }).union(last);
}for (var i = 1; i <= count; i++) {
  last = CSG.sphere({ center: [start, start + i*dist, 0], radius: radius }).union(last);
}
return last