13 links have been added on 4 ideas about #vintage.
  1. The second-hand clothing marketplace is a lucrative industry worth a substantial amount of money.

  2. not possible according to Instructables users – however, easy with digital glasses.

  3. Colorblind glasses exist already https://www.treehugger.com/inventor-creates-sunglasses-that-make-people-colorblind-4863170