module round_with() {
	if ($preview) {
		children([1:1:$children-1]);
	} else {
		minkowski() {
			difference() {
				children([1:1:$children-1]);
				minkowski() {
					difference() {
						minkowski() {
							children([1:1:$children-1]);
							children(0);
						}
						children([1:1:$children-1]);
					}
					children(0);
				}
			}
			children(0);
		}
	}
}

module round_edges(r) {
	round_with() {
		sphere(r, $fn = 8);
		children();
	}
}

// deprecated
module tx(l) { translate([l, 0, 0]) children(); }
module ty(l) { translate([0, l, 0]) children(); }
module tz(l) { translate([0, 0, l]) children(); }

module rx(a) { rotate([a, 0, 0]) children(); }
module ry(a) { rotate([0, a, 0]) children(); }
module rz(a) { rotate([0, 0, a]) children(); }

module sx(a) { scale([a, 1, 1]) children(); }
module sy(a) { scale([1, a, 1]) children(); }
module sz(a) { scale([1, 1, a]) children(); }

// capital letters are ugly, but more visible in short identifiers
module Tx(l) { translate([l, 0, 0]) children(); }
module Ty(l) { translate([0, l, 0]) children(); }
module Tz(l) { translate([0, 0, l]) children(); }

module Rx(a) { rotate([a, 0, 0]) children(); }
module Ry(a) { rotate([0, a, 0]) children(); }
module Rz(a) { rotate([0, 0, a]) children(); }

module Sx(a) { scale([a, 1, 1]) children(); }
module Sy(a) { scale([1, a, 1]) children(); }
module Sz(a) { scale([1, 1, a]) children(); }

module Mx() { for (s = [-1, 1]) Sx(s) children(); }
module My() { for (s = [-1, 1]) Sy(s) children(); }
module Mz() { for (s = [-1, 1]) Sz(s) children(); }

eps = 0.01;
infty = 100;