A conveyance company occasionally orders candy-cane bends. The last order was for a tight 18″ Radius on a 4″ OD 180 Deg tube.
It takes a certain technique to make these kinds of bends and to avoid the stresses that would generally pull the bend inward or outward. Additionally, bends of all types, but especially this type act as thermometers moving with temperature changes (and especially to radiant heat).
Nevertheless, they make a nice picture.