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.
Cute mini-cat bookmarks (foreign language instruction - picture only) - make a paper pattern first. Glue felt cut-outs onto craft stick dotted with paw prints. Tie with twine or mini-ribbon. Cute idea for a party favor!