Picture of how to renforce card board
this is a handy way to stop card board boxes splitting and other things

you will need:

corrugated card board

wooden skewers

insulating tape


Step 1:

Picture of
cut your card board to shape [make sure it is not longer than the skewers]
Hmm. I probably would have just used epoxy or superglue instead of the tape. Then, it would look like plain cardboard, well, from the right view.
Pretty easy and useful!