Takes a bit of thought but quite easy if you’ve done some machine sewing before BUT remember only sew one square gusset on the liner so can turn it inside out through the unsewn gusset (corner) then hand stitch the second one inside.
For my garden quilt. The Bandana quilts are cute, too. Bandana quilts with only four bandanas! You need one for the center, one cut into fourths from the corners for the "middle layer" , and two cut in half from corner to corner for the outside corners.