Make your own DIY overhead projector for tracing wall murals. Make a makeshift projector using a box, a lamp and some tape. Project the transparency onto the wall. Use a light bulb without the "frosting" on the inside for a clearer picture.
Make your own projector using a shoe box, duct tape, magnifying glass, and your smart phone! That's crazy! A projector would be nice.If I made this and used it during an observation either I could save us a lot of money or get my own projector.