A shell stitch is composed mainly of double crochet stitches into a chain space or previous stitch. The basic shell stitch looks 'stacked'; the shells are made in rows atop each other.
With any yarn and hook, make a multiple of 5 stitches + 3.
The 5 dc shell:
Row 1: Skip the 3 stitches from your hook, *make 5 dc in next stitch (shell made), sk 2 sts*, repeat across row, end with 1 dc in last ch or st.
Row 2: Ch 5, *5 dc in 3rd stitch of shell below*, repeat across row, end with 1dc in last ch or st.
Repeat row 2.
With any yarn and hook, make a multiple of 7 stitches + 4.
The 7 dc shell:
Row 1: Skip the 3 stitches from your hook, *make 7 dc in next stitch (shell made), sk 3 sts*, repeat across row, end with 1 dc in last ch or st.
Row 2: Ch 5, *7 dc in 4rd stitch of shell below*, repeat across row, end with 1dc in last ch or st.
Repeat row 2.
Variations: