Here's how.....

Get 1.5-2 yards of fleece.  Trim off the selvages.  Then, cut 3" squares out of each corner.  Fold over each side 2-3 inches and zig zag the flap down.

 Then, cut perpendicular slits into the flap-about 1/2-3/4 in. wide.  (cut in to about 1/4" in. of the stitching) No need to measure, just eyeball it.

 Then, hand crochet around the sides by looping one loop over another.

 All done!  Pretty, huh?