Can You Fill Exactly 50%?

Can you fill half a shape, exactly 50%, by feel alone? Hold the button and watch the shape fill from the bottom. Release the moment you think exactly half is covered. Your score is the percentage error from the 50% mark. Easy is a rectangle that fills slowly; Medium is a circle that fills faster; Hard is a hexagon that fills fastest and hides the halfway line until you let go.

How to Play

1. Press and hold the fill button. The shape begins filling from the bottom.
2. Release when you judge that exactly half the area is filled.
3. Your fill percentage and error from 50% are shown immediately.
4. On Hard the halfway guide is hidden while you fill, so you judge the middle by eye.

Why It's Hard

The fill line rises at a steady speed, but in a circle or hexagon the amount of colour does not. Near the bottom the shape is narrow and the colour creeps in; around the middle the shape is widest and the colour seems to rush. Your eye reads that surge as "nearly there" and lets go early, or overshoots while waiting for the fill to look half done. Reaction time adds to it: on the faster shapes, a late release of a fifth of a second costs several percent.

Tips

• All three shapes are symmetric top to bottom, so half is always the vertical middle. Watch the height of the line, not the amount of colour.
• Start letting go a moment before the line reaches the middle; your release lags behind your decision.
• Practice on the rectangle first to calibrate your timing before the faster circle and hexagon.

FAQ

Is the fill measured by area or height?

By area: your result is the share of the shape covered when you let go. Every shape here is symmetric top to bottom, so half the area always sits at the vertical middle.

Why does 50% feel different on each shape?

The halfway point never moves, but the colour spreads at different rates. A rectangle fills evenly, while a circle and a hexagon fill fastest across their wide middle, which makes the last moments before halfway feel rushed.

What percentage error is considered a good score?

Within 2% of half is excellent. Most players land within 5% on the rectangle and within 8 to 12% on the faster circle and hexagon.