We all know that a histogram is a graphical representation of the dark and light pixels in an image; it shows how many pixels of the varying shades â€“ from the blackest to the lightest â€“ you have in a photo.
David Friedman of IronicSans.com turned the idea around and created an image in the histogram itself and hid it in an image that looked like a gradient fill. Then he posted a challenge to readers to find the hidden image.
Genius. In the link below, he detailed how he did it, in the process explaining what a histogram is really like.
Unfortunately, the image he used was an old one which still showed the tragic twin towers of the WTC, and it sparked a distracting debate in another direction. Ironic, eh?