“I found this piece of glass that changes colors depending on how you look at it. Where could this have come from?”
Answer: “It’s a dichroic glass filter used for color correction in photographic printers.”
I think it might be the 95th time I have seen that picture on this site, and yes, old toothbrush :)
Yeah, how could a sponge be used for RFID?
Yeah, Izi, we've been over this before.