You will need 2 colors
White and an alternate color of your choice...
To make a 6" square chain 23 in worsted weight yarn
Sc in 2nd ch from hook and across, ch 1, turn (22 sts)
Sc in each st across. ch 1 turn
Repeat 2nd row for a total of 17 rows.

Now do 2 rows of sc around the square in black or alternate color.
You can also do these squares in afghan stitch adding the heart as you go.