Very simple square coaster is only used single crochet and chain.
Putting fabric on wrong side make coaster much nicer.
3.50mm crochet hook
Fabric for lining(desired)
sc = single crochet
sc2tog = single crochet 2times together
sl st = slip stitch
Row1: ch26, sc2tog in 2nd and 3rd ch from hook, ch1, [sc2tog in next 2ch, ch1] repeat across, 1sc in last ch. Turn.
Row2: ch1(do not count as sc), 1sc in sc below, skip next ch1 sp, [ch1, 1sc in next sc, skip next ch1 sp] repeat across. Turn.
Row3: ch1(do not count as sc), [sc2tog in next sc and ch1 sp, ch1] repeat across, 1sc in last sc of row below. Turn.
Row4-23: repeat row2 and row3.
Fasten off. Weave in ends.