How Centered or Not works

How rounds are made

Every card front is a scan from the owner's own collection, straightened and cropped to the card's outer edges.

The answer is measured on the scan: the card's four outer edges and the four inner printed-border lines, each found along many lines per side, give the left/right and top/bottom splits.
The measurement was checked against hand-placed lines before any card was scored, and every scored card was checked by eye with its lines drawn over it. Border types it can't measure reliably stay unscored.
Cards not measured yet save your lines without scoring them.
Your miss is the average of the left/right and top/bottom misses, in ratio points: within 1.0 is dead-on (and a bonus), within 2.5 sharp, within 5 close.
Points are measured against the typical split: the middle left/right and top/bottom splits of the measured cards from the same era, a read anyone could make without looking. It scores 0, like Can't measure. You earn a point for every ratio point your miss beats the typical split's miss by, and lose one for every point it falls short, up to 3 either way.

Answers stay on the server until you answer.
Only rounds with a known answer are scored. Nothing is scored for speed or for agreeing with other players.
Player percentages appear only once an item has at least 100 counted answers. They describe players of this game, not the public. It is not a poll.
Each network counts at most 3 answers per item, and hosting-provider networks never count. None of this changes your own score or streak.