For the lid, you cut a poster in 4.
The complete poster measures 48" by 32" so you can make 4 lids each from a piece 24" by 16"
The lid need to fit tightly to avoid blowing off. It measures 18 and a wee bit by 10 and a wee bit so the sides are a wee bit under 3"
If you make it too tight you can correct things by slackening the duct tape.

I re recorded an old favourite this morning.