I find this statistical study by Slate's Ben Blatt fascinating: Waldo—Wally in Europe—isn't placed randomly on the page. That means that you can find him faster if you follow this simple trick:
Don't look at the corners or the center of the drawing. Leave those till o the end, in case you don't find him in the donut-shaped area where you should be looking.
Why does this trick work? It's simple statistics. Whitenoise writer Ottermann summarizes Blatt's findings:
If Waldo were truly placed randomly, he would be within 1.5 inches of the top or bottom of the pages 25% of the time. Instead, he's there only 12% of the time.
Most Waldo drawings have a 'postcard' from Waldo in the upper left corner that takes up about 15 square inches. In the corresponding area on the opposite page, Waldo only appeared 4 times, which is slightly less than he would have been expected to appear there had he been placed randomly.
In the 2.5-inch band across the center of the page, in between the two Waldo rich bands, Waldo only appears 8 times, or 13% of the time.
Only twice was Waldo placed within 1.5 inches of a corner.