3D Hologram smartphone

LONDON – If you happen to have an old CD case and a few basic tools lying around, this one will make a pretty cool party trick.

British YouTuber and independent tech reviewer Mrwhosetheboss has uploaded an instructional video on how to turn any old smartphone into a 3D hologram projector – using nothing more complicated than a sharp knife, a ruler, a pen and paper, an old CD case and four squares of sticky tape.

1. First, mark out the following shape.

This will be a paper template. The shape should measure roughly 6cm wide at the bottom and 1cm at the top by 3.5cm high. "You can always try and double those or triple those, " says Mrwhosetheboss about the measurements, "and you will get a nicer effect."

4. Carefully cut it out with your knife.

You'll need four of these shapes in total to make up your mini projector.

5. Stick the shapes together with some tape.

"Try and fasten them together like this using a little bit of tape, " says Mrwhosetheboss. "I originally tried glue but then they just fell apart, so this seems to work fine."