I made a camera obscura

Bought black plastic from the garden centre. Cut a hole in it the size of a 2€ coin. Hung it up in the window and taped it down. I got a projection on the back wall of the room, but it was more shadows than a real picture... I would go as far to say that it was shit. Perhaps I need a lens for it to work properly... and I don't think Maija likes it. The room has to be clear and bright for Janet when she comes, so I expect I will take it down.