There's isn't much to add to the above GIF, other than that I think it's a really cleverly designed and demonstrated concept. The idea of CMYK printing is nothing new to me; I've been interested in the physics used in forming imagery since I first noticed the tiny circles of colour (read: pixels) on a Coca-Cola vending machine image at school. Heck, I've worked for a newspaper company right next to the printing warehouse and currently program for a company that specialises in bulk printing!
That said, I still find the concept of combining varying levels of cyan, magenta, yellow and black to form a seemingly full-colour image a little magical. I'm clearly not the only one, too, and this was a little too well executed not to share.
PS: This is also the first time I've ever posted using a card. Having finally seen the process in the wild, this is also a little bit magical. I'm just a little concerned its magical towards the Dark Arts end of the spectrum.
Update 20/05/20: Image URL has been altered. No longer clear what the "card" was being referenced so have replaced with a standard GIF, hosted externally.