More spiral pattern toward the ends is produced by which rod?

• A. Convex Rod
• B. Concave Rod
• C. Straight Perm Rod
• D. Bookend

Answer: (B)

Understanding how a perm rod shapes the curl is key: the rod’s form determines how tightly and where the hair wraps around it along the strand. A concave rod curves inward along its length, which guides the hair to wrap in a way that accumulates more spiral features toward the ends of the strand. In practice, the hair near the tips tends to take on a longer, more winding path around the rod, creating those pronounced spiral patterns at the ends while the middle remains less spiraled. This contrasts with other rod shapes, which distribute the curl differently and don’t emphasize the ends in the same way.