Spot The Difference Generator
Two scenes, side by side, with a fixed number of differences between them. What makes this one worth printing is the answer key: every difference is one whole thing changed — a mug gone, a rocket moved, a butterfly turned round, an apple where a tree was, two kites instead of one — so the key can name each one and say where it is. Nothing is faded, speckled or shifted by a hair's breadth, which means there is nothing to argue about when someone says they have found them all.
What this generator does
Scatters a scene of objects with nothing overlapping, copies it, applies a set number of named changes to different objects, then compares the two finished scenes to write the key.
How to use this tool
- Choose how many differences you want and how crowded the scene should be.
- Print or copy both scenes; they are drawn at the same size so they line up.
- Find the differences. Each one is a whole object, never a smudge.
- Show the answers to check, or copy the answer list to keep separately.
- For a harder round, ask for a crowded scene with the same number of differences.
Understanding the controls
- Differences
- Five to ten. A scene will not carry more than half its objects changed and still read as the same scene, so ten needs the crowded setting.
- Scene
- How many things are on the sheet. This is what makes the puzzle harder — more to look through, and smaller moves — rather than a fainter line.
- Seed (optional)
- Type anything to rebuild the same pair later, which is how you reprint a sheet you have lost. The seed repeats a puzzle; it offers no cryptographic strength and keeps no secret.
Common use cases
- A quick activity page for a classroom, a party bag or a long journey
- A puzzle where the answer key is exact, so nobody argues about a near miss
- An observation exercise that can be made steadily harder without being made blurrier
- A pair of sheets to print now and keep, rather than one found online
- Reprinting the identical pair later from its seed
How this generator works
A scene here is a list of placements rather than a picture: which thing, where, how big, turned how far, drawn in which pattern, and how many of it. The picture is what gets drawn from that list afterwards. That is what makes the answer key exact. The usual way to build this puzzle is to draw one picture, copy it and change some pixels, after which the only honest key is “somewhere around here”, because nothing recorded what changed. Here the second scene is the first with named changes applied to named objects, so the two lists can be compared field by field — which is exactly what happens before a pair is published, with the key hidden, to check that the comparison finds those changes and no others. Objects are placed by trying a spot and trying again if it is taken, so nothing overlaps. And a turn is only used when it actually moves the shape: a rosette turned a quarter is almost itself, which was measured rather than guessed, so such turns are never offered as differences.
Randomness and fairness
The scene, the changes and which objects they land on come from your browser's cryptographic random source. A seed replaces that with a repeatable one so the same pair can be printed again. A seed here is for reproducibility, not cryptographic strength, and it keeps nothing secret.
For how randomness is produced across the whole site, see how Generate Random works.
Limitations and good to know
- A scene carries at most half its objects changed, so ten differences needs the crowded setting.
- Differences are always whole objects; there are no partial or subtle ones, which is the price of an exact key.
- A change of size is not offered: small enough to be fair is thinner than the line, and large enough to see reads as a move.
- Objects never overlap, which keeps the key honest but makes the scenes tidier than a hand-drawn one.
Privacy and your data
Both scenes and the answer key are made in your browser. Nothing you type as a seed, and no puzzle made from it, leaves the device.
Related generators
- Picture Maze GeneratorMakes a maze cut to the shape of a picture — a cat, a rocket, a leaf — that is still a proper maze, with one route through and every square reachable.
- Connect the Dots GeneratorPrintable join-the-dots pictures with the dots numbered in order, from ten dots to ninety, with the finished picture on a second page.
- Colour by Number GeneratorPrintable colour-by-number pictures where every area has a number, the key lists exactly the colours used, and two areas that touch never ask for the same one.
- Finish the Drawing GeneratorHalf-finished pictures to complete, with the missing part chosen by a rule you pick — a half, a quarter, whole pieces, or a break in the outline — and the finished drawing on the answer page.
- Mirror Drawing GeneratorHalf a picture with a fold line ruled down it and the other half to draw — down the middle, across the middle or corner to corner, with the completed drawing as the answer.