The lightest breeze will make them spin. Cleverly made by having many strips of wood threaded onto a central axis and then decorated. They are painted on both sides and are extremely effective. They are delivered flat and you simply 'twist' them, one section at a time into the desired shape. I have shown two ways of doing this one with a full double helix and one with a single helix. You can vary the effect depending on how far you open up each section.