a candelabra (lichter); loose leg in chair or table; assembling model plane model boat; wheel of a stroller; winding a watch;
understanding Important Concepts in the Melacha of 'מכה בפטיש' (Final Action);
floor Drain with Hinges or Handle, Shelf in a Bookcase with Hinges, and the Use of a High Riser or Sofa Bed on Shabbos;