Printable lens hoods

It’s been a long time since I have seen such a brilliant idea. This site offers free printable PDF documents that can be folded into lens hoods.
I guess they are not very sturdy, and I wouldn’t trust one to protect my camera lens from getting hit. But I will use one just for the heck of it.
Ok, so he site is at I have one idea for improvement though, the patterns can be printed on polypropylene sheet, and take more abuse.