How to spot differences faster
Spot the difference means finding what changed between two nearly identical pictures. The idea is simple, but a few habits save a lot of searching. Here's the basic order, how this site builds its puzzles, and tips for going faster.
What spot the difference is
Take one picture, change a few spots in a copy, put them side by side and ask people to find the changes. It has run in newspapers, magazines and children's books for a long time, so nobody needs the rules explained.
A good puzzle is neither obvious nor impossible. This site sets numeric limits for that and builds every puzzle inside them.
The basic order
Scan both pictures once to learn the layout: where the people, buildings and trees are.
Then go area by area. Look at the top left corner of one picture, then straight at the same corner of the other. Smaller areas mean fewer misses.
Found spots get a circle, so you never need to recheck them. The counter at the top shows what's left.
How this site builds its puzzles
Each puzzle starts from a painting that The Met has made free to use and adapt. For each date and level we pick one painting and change a few spots. Those changes aren't in the original work.
There are four kinds of change: recolor an object, make it lighter or darker, cover a spot with a nearby patch to remove or duplicate something, and mirror a small area left to right. Hard puzzles only change shapes, never color or brightness.
Differences are kept apart so one tap can't catch two, and none sit right on the edge. Changes that are too faint don't make it into a puzzle.
Taps a little outside a difference still count. Tapping anywhere else locks the pictures for 3 seconds.
Basic tips
Start with color. Clothes, roofs and flowers stand out the moment their color changes.
Look for missing things. A window, a person or a cloud that vanished leaves a gap in only one picture.
Mirrored spots show up in writing, the direction someone faces, and slanted lines.
On a phone you can pinch to zoom. Larger text stacks the two pictures big, one above the other.
Going faster
Move your eyes in one direction. Scanning in bands from top to bottom stops you from checking the same place twice.
Flicking your eyes quickly between the pictures can make a change seem to blink. It works best when both pictures fit on screen at once.
A wrong tap costs 3 seconds. If you're not sure, one more look is usually faster.
Where people get stuck
Can't find the last one? Check near the edges and inside dark shadows. Brightness changes are hard to see in dark areas.
Tapped and got a wrong? Aim for the middle of the difference. Tapping well outside it counts as wrong.
Really stuck? Show answers circles what's left. That run isn't ranked, but past puzzles are waiting in the archive.