Overshot Double Crochet. Make the chain foundation, and three extra chains to turn.
Row 1. Work 1 D.C. into each foundation chain.
Row 2. Chain 3 and turn, work 1 D.C. forward around post of 2nd D.C. of previous row. Work 1 D.C. forward around post of 3rd D.C. of previous row, * 1 D.C. around post of next D.C. taken around back of stitch, 3 D.C. forward around post of next 3 D.C. Repeat from * across row, and end 3 D.C. forward.
Row 3. Ch. 3 and turn, 1 D.C. in each of next 2 D.C., * 1 D.C. forward around post of next D.C., 1 D.C. in usual manner in each of next 3 D.C. Repeat from * across row.
Repeat Rows 2 and 3 for pattern.
Source: Complete Guide to Modern Knitting and Crocheting
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