My first pattern.

Round 1: 6 SC in a magic loop
Round 2: Stitch in the back loop only, increase every stitch (12 SC)
Round 3: Stitch back loop only, (3 SC, INC) around (15 SC)
Round 4: (Last round of back loop only): DC around (15 DC)
Round 5: SC around (15 SC)

Repeat rounds 4 and 5 (do not work in back loop only any further) until you’ve reached your desired height.