Double Twist on an Astragal
An astragal is molding profile composed of a half round surface surrounded by two flat planes (fillets). An astragal is sometimes referred to as a miniature torus. It can be an architectural element used at the top or base of a column, but is also employed as a framing device on furniture and woodwork.
A. Rosengarten, W. Collett-Sandars A Handbook of Architectural Styles (New York, NY: Charles Scribner's Sons, 1895)
Courtesy the private collection of Roy Winkelman