This pattern is written for two colors. Color A is the color of the crown and of the textured stripes, and I recommend using a solid color to bring out the textures. Color B is the color of the ribbed brim and of the other stripes, and a variegated or self-striping yarn would look especially striking because of the alternating single crochet/double crochet pattern of those stripes. You can also work this beanie in a single color if you prefer.

This hat is sized for an average adult. To adjust the size, you can use a larger or smaller hook.

The name of this pattern comes from the name of a pioneer in the study of hyperbolic surfaces, Nikolai Lobachevsky.

Materials:

• Worsted/aran (#4) weight yarn, about 75-90 yd. (69-82 m) for color A and 100-120 yd. (91-110 m) for color B
• 5.5 mm (size I-9) crochet hook
• Yarn needle