This interesting hat is knit using 2 colours of fingering weight yarn, 50 grams each. Colours change every 2 rows with the yarn carried up the side of the work. The hat is knitted flat, then seamed in the back. Noggintopper is a regular beanie and also included in the pattern is Explorer - an extra tall hat with an optional pompom on the end.
The example shown here used 2 colours of self patterning sock yarn (Opal) however it can be done in 2 solids or 1 solid and one patterned or hand dyed. The options are entirely up to you!