Techniques used in this pattern (British term / American term):

Chain stitch – ch

Treble / Double crochet – tr / dc

Shell - 2 tr/dc + 2 ch + 2tr/dc in the same stitch

Stitch - st

Make 9 foundation chains.

Row 1: 4 ch miss, shell in next ch, 6 ch, 1 dc/sc in last ch, turn.

Row 2: 3 ch, 12 tr/dc in space of 6 ch, shell in shell, turn.

Row 3: 2 ch, shell in shell, 12 tr/dc over tr/dc below, 1 tr/dc in third ch, turn.

Row 4: 3 ch, 12 tr/dc over tr/dc below, shell in shell, turn.

Row 5: 2 ch, shell in shell, 12 tr/dc over tr/dc below, 1 tr/dc in third ch, turn.

Row 6: 3ch, *2 st miss, work shell in space between tr/dc; rep from * 5 times, shell in shell, turn.

Row 7: 2 ch, work shell in shell to the end of row, turn.

Row 8: 2 ch, work 6 shells {3 tr/dc + 1 ch + 3tr/dc} in shells below, shell in shell, turn.

Row 9: 2 ch, shell in shell, work 6 shells {4 tr/dc + 1 ch + 4tr/dc} in shells below, turn.

Row 10: 2 ch, work 6 shells {5 tr/dc + 1 ch + 5tr/dc} in shells below, shell in shell, turn.

Row 11: 2 ch, shell in shell, 6 ch, 1 dc/sc in next shell, turn.

Repeat 2 – 11 rows until you have reached your desired length.