I used a size H hook.
sc in 2nd ch from hook and across for first row
ch 1, turn, sc in 1st sc, *sc & dc in next sc, sk next sc* - repeat this format across for row, ending with sc in the last sc, ch 1 and turn
Repeat row 2 until desired size. I made mine 30 rows.
Then, sc in a contrasting color around the outside for the border. End with sl st, then continue with a sl st around the outside to complete the look.
Weave in ends.
My finished mats measured roughly 11 1/2" x 17"
You could also make coasters with this pattern!