Concept 8 of 8
Spot the Odd Figure: Check One Thing at a Time
Today's big idea
Pick one feature and sweep it across every figure before trying another.
Sweep one feature across every figure, and the odd one breaks exactly that feature.
How it works
👀 What's going on?
Four drawings sit in a row and three of them are exactly the same. Staring at all four at once makes them blur together. Looking at one small thing across all four does not.
💡 Here's the trick
Look at the four faces above. Rather than comparing whole faces, pick a single feature and check it across the row. Count the eyes: all four have two. Check the mouth: all four have one. Count the dots on the cheek, and the third face has an extra one. Found.
🪄 How to do it
- 1.Pick one small feature, as the faces above share eyes, a mouth and cheek dots.
- 2.Check that single feature across every figure before moving on.
- 3.Stop the moment one figure disagrees with the other three.
✍️ Try it
Four squares each carry a dot in a corner, and three of them are top-left. Then four flags each have three stripes, except one.
Checking corners across the row, three dots sit top-left and one sits top-right, so that fourth square is the odd one. Counting stripes across the flags, three show 3 and one shows 2, which finds it in a single pass.
⚠️ Watch out
You might be thinking the odd one will jump out at you. It usually does not, which is the whole point of the puzzle. Guessing costs more time than one careful pass.
🌟 Why this matters
Proofreading, checking change in a shop and spotting a wrong ingredient all work this way. Checking one thing at a time is what makes a careful eye reliable.
Exam tip: Name the feature you are checking out loud before you start the pass.
Watch me solve one
Quanta solves it
“Watch how I think through one of these — then you try.”
THE PROBLEM
“Four flags look alike. Three have a star in the corner and one has a circle. How do you find the odd flag fastest?”
- 1
Staring rarely works
Four near-identical figures blur together when taken in at once.
- 2
Sweep ONE feature
Look only at the corner shape on flag 1, then 2, then 3, then 4.
- 3
Stop at the first disagreement
Three stars and one circle: the circle flag breaks the sweep.
- 4
Answer ✓
Sweep the corner shape across all four
Now you try one — same steps, different story 👇
See it in action
⚡ Time to play!
Pick a feature, sweep the whole row, stop when one disagrees.
FEATURE CHECKER · ROUND 1 OF 3
Step 1 · which feature will find it?
Quick check
✅ VERIFICATION
Four drawings are the same except one. What is the surest way to find the odd one?
⚡ Finish the activity above first to answer.
Keep going!