The pattern is created by calling 102 iframes inside a single table cell with a width set to 700 pixels via the deprecated `width` attribute

Each iframe is loaded with a random pick from one of twenty possible pages ordered from 1 to 20

Each of the twenty pages was statically generated with a random color background and a random interval to wait before using a meta tag redirect to move to the next page in the order

Said another way, each tile is playing the same sequence of colors at the same cadence as all the other tiles. The only difference between them is which of the twenty possible positions they start at (plus a little drift in load timing)

So, the pattern in pseudo-random but it's the same each time the page is loaded. It's a bit like a one-time pad being used over and over again. (At least, until I regenerate the site with a new set of random output.)