for (int i = 0; i < e_count; ++i) {
BodyDef bd = new BodyDef();
bd.type = BodyType.DYNAMIC;
bd.position.set(-4.5f + 1.0f * i, 5.0f);
Body body = getWorld().createBody(bd);
body.createFixture(fd);
if (i > 0) {
Vec2 anchor = new Vec2(-5.0f + 1.0f * i, 5.0f);
jd.initialize(prevBody, body, anchor);
getWorld().createJoint(jd);