/* This creates a twisted extrusion of 5 unioned circles
 * with gratuitous amounts of rounding. Try it out! */

linear_extrude (height = 40, twist(h) = 35*cos(h*2*pi/60))
  union ( r = 8) {
    circle (10);
    translate ([22,0]) circle (10);
    translate ([0,22]) circle (10);
    translate ([-22,0]) circle (10);
    translate ([0,-22]) circle (10);
  }