Use 2 balls of cotton yarn 8/4 at the same time.
Start: Use hook size 4.5 mm and chain (ch) 80. Start in the 2nd stitch from the hook.
ROW 1 Use hook size 4 mm and make 1 single crochet, 39 bobble stitches, 1 ch, turn
ROW 2 79 single crochet, 1 ch, turn
ROW 3+ Repeat rows 1 and 2 until you end up with 39 bobbles in width and 37 bobbles in height.
The last row must be row 1 (a bubble mask row).
Fasten off and weave in ends.