Lemon peel crochet stitch
Alternating US single and double crochet stitches make a pebbled fabric.
Counted practice swatch
Chain 21. Start in second chain, producing 20 actual stitches.
Work the repeat
Row 1: [sc in next chain, dc in next chain] 10 times. Every later row: ch1, turn; [sc in next dc, dc in next sc] 10 times. The turning chain does not count.
Read the fabric
A short stitch sits above a tall stitch after turning. Repeating sc above sc would build columns rather than lemon-peel texture.