This pattern is available on Ravelry.
A textural delight, the slip-stitch pattern of the Heidi Hat, designed by Carrie Bostick Hoge, is worked in the round from the bottom up, in three colors of sportweight Chickadee.
1 skein each:
kumlien’s gull 152
16” circular in size US 4 / 3.5 mm
set dpns in size US 4 / 3.5 mm
Long-tail cast on, pom poms (links provided); decreasing, slipping stitches, working with multiple colors.