Final answer:
A spiral perm wrap is done by wrapping the hair perpendicular to the rod in overlapping concentric layers, resulting in vertical curls.
Step-by-step explanation:
The type of perm wrap that is wrapped perpendicular to the length of the rod, in overlapping concentric layers, is called a spiral perm wrap. This method uses chemicals to change the hair structure and is wrapped in a way that the coils of hair follow the length of the rod, which results in a vertical curl pattern. This is opposed to a traditional perm wrap which results in a horizontal curl pattern. Spiral perms give a more defined, springy curl to long hair, creating a full-bodied look. Unlike chemical straightening or relaxing, where hair is flattened, in a spiral perm, the hair takes on the shape of the curls defined by the spiral wrapping method around the rods.