module sholder_strap(strap_len = 400, blobs = [150, 200, 250], blob_d = 10, thikness = 0.5, width = 40, hole_d = 10) {
    difference() {
        union() {
            linear_extrude(height=thikness)
            hull() {
                circle(d=width);
                translate([strap_len, 0])
                    circle(d=width);
            }

            for (i=blobs)
            translate([i, 0, 0])
                sholder_strap_blob(d=blob_d);
        }
        translate([0, 0, -thikness/2])
            cylinder(h = thikness*2, d = hole_d);
        translate([strap_len, 0, -thikness/2])
            cylinder(h = thikness*2, d = hole_d);
    }
}
module sholder_strap_blob(d) {
    difference() {
        sphere(d=d);
        translate([0, 0, -d])
            cube([2*d, 2*d, 2*d], center=true);
    }
}

sholder_strap(
    strap_len = 400,
    blobs = [124, 200, 275],
    blob_d = 10,
    thikness = 0.4,
    width = 40,
    hole_d = 10
);