What balance point measures
A shape appears and you click once, marking where you think it would balance if you put a pin through it. The true centre of mass is then revealed, along with how far off you were in pixels. Five shapes make one run, and your score is the average closeness.
The answer is the area centroid, computed exactly from the outline rather than estimated. For a uniform flat shape that point is where it balances, and it has a property most people find counterintuitive: it does not have to lie on the shape at all. Bend a shape into a horseshoe and its balance point sits in the gap, touching nothing.
Most of the shapes here are bent, and in a little over half of them the balance point falls in empty space. That is the interesting part of the task. The eye wants to place the centre somewhere inside the material, usually near the middle of the bounding box, and on a curved or L-shaped form that answer is systematically wrong.
What counts as a close click
| Miss | On a 400px shape | Score |
|---|---|---|
| Dead on | 0px | 100% |
| Very close | 8px | 93% |
| Close | 16px | 87% |
| Fair | 24px | 80% |
| Middle of the box | 23px | 81% |
| Well off | 60px | 50% |
| Average over five shapes | Percentile |
|---|---|
| Below 64% | Bottom tenth |
| 64 – 76% | Below average |
| 76 – 85% | About average |
| 85 – 91% | Above average |
| 91 – 95% | Strong |
| Above 95% | Top few percent |
How to find the centre faster
- Do not click the middle of the shape. The centre of the bounding box scores about 81% on average, which sounds respectable and is exactly the trap. On bent shapes it is reliably wrong in the same direction, and correcting for that is most of the available improvement.
- Follow the mass, not the outline. Ask which parts are thick and which are thin. A long narrow arm carries far less weight than a short fat one, so the balance point sits much closer to the fat end than the shape's apparent middle suggests.
- On a bend, move toward the inside. For anything curved like a C or an L, the centre of mass pulls into the hollow. On deep bends it leaves the shape entirely. If a shape wraps around empty space, your click probably belongs in that space.
- Split it in two and balance the halves. Mentally cut the shape into two chunks, find each chunk's rough centre, then place your click on the line between them, nearer the heavier one. This is more accurate than judging the whole thing at once.
- Squint until the detail disappears. Blurring removes the outline your eye is over-reading and leaves the distribution of mass, which is the thing you are actually trying to locate.
Frequently asked questions
How is the balance point calculated?
It is the area centroid of the outline, computed with the shoelace formula. For a flat shape of uniform thickness that is exactly the point it would balance on.
Why is the answer sometimes outside the shape?
Because the centre of mass is an average position, not a physical part of the object. A horseshoe balances at a point in the gap between its arms. Just over half the shapes here are bent enough for this to happen.
What is a good score?
An average above 85% over five shapes is above average, and above 91% is strong. Clicking the middle of the bounding box every time scores around 81%, so beating that consistently means you are genuinely reading the mass.
Is this the same as the centre of the shape?
No, and that is the whole game. The centre of the bounding box, the middle of the outline and the centre of mass are three different points, and they only coincide on symmetric shapes.
Are the shapes the same for everyone?
On the daily, yes. Everyone gets the same five shapes on the same day, with one attempt. Practice mode generates fresh random shapes and never affects the daily.
Does this measure anything real?
It measures how well you locate a centre of mass by eye, which is a real perceptual and physical-reasoning skill. It is not an intelligence test and predicts nothing beyond itself.