What type of curls have larger center openings and are fastened to the head in a standing position on a rectangular base?

The correct answer is barrel curls. Barrel curls are characterized by their larger center openings and are secured to the head in an upright position, utilizing a rectangular base. This specific formation allows for the creation of volume and bounce in the hair, making them ideal for producing soft, well-defined curls. The technique involves wrapping sections of hair around a curling tool or roller in a manner that promotes the desired shape, and once set, results in curls that have a more mature, polished appearance compared to other curl types.

Cascade curls, while also creating volume, typically involve a different technique and arrangement on the head. Spiral curls refer to a tighter, helix-like curl pattern, while pin curls are usually create flat curls that lie close to the scalp, lacking the larger base and central opening distinctive to barrel curls. Understanding these distinctions can aid in selecting the appropriate curling method for a desired hairstyle.