This is the most incredible visual trick I've ever seen, one that will make your entire reality melt -- literally deforming everything in front of your eyes, shrinking and expanding objects around you. It's mind-glowingly trippy (WARNING: Don't try this if you are epileptic. It may cause seizures.)
1. Make the video below full screen. The video must cover your entire screen.
2. Play it and focus your eyes on the centre for the entire duration of the video -- around 30 seconds. Watch the entire video -- the effect will be stronger and last longer.
3. Then look around your house or your office and see how the world deforms in real time. It will look something like the image above, but it will morph and move! At least in my case, the effect lasted for quite a bit. So trippy.
You can download an iOS app with this effect so you can make everyone flip with your iPad at work or home.