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.
Bento bag with drawstring closure box bag no rim. Free pattern and tutorial to sew a lunch box bag with drawstring cover. The cover prevent the contents from falling out. Great to carry an on-the-go small craft project.