Experiment 08 / One Move
One reading.
One reversal.
Five numbers. A chosen target. The mean or median is closer—until you change one reading. Find the smallest move that gives the other estimate a strict lead.
Round 1 / 3
The narrow crossing
The mission
The open run / this session
Your run, in motion.
0 flipped · 0 exact minimums
Tap a completed case to improve your move. Reloading starts a fresh run.
2. Set a new value
Your proposed verdict stays hidden until you commit. The plot marks the original and proposed reading.
Drag for a rough move; type up to four decimal places to find the exact minimum.
Optional / solve your way
A little perspective?Attempts this puzzle: 0
What changed?
Error from the chosen target · shorter bar is closer · one shared scale
The move under the hood
Readings in ascending order · coral marks your reading · mint marks the middle
Five routes. One verdict.
Mathematical receipt / independent integer checkWhy no smaller move wins
Write every input in exact four-decimal integer units. For the moved reading u, let S be the sum of the other four, T the target, and b and c their two middle values. The signed error gap is:
D(u) = |S + u − 5T| − 5|clamp(u, b, c) − T|Negative means the mean is closer; positive means the median is closer; zero ties. The formula is a straight line between its mean-zero, target, and middle-reading breakpoints. Checking each interval’s endpoint signs and first opposing grid point covers every possible move, including unreachable routes. The adjacent grid point shown for each route still fails to reverse the winner.
This is a proof about this finite puzzle’s chosen target and four-decimal rules, not evidence that a target is true or that either estimator wins on real data.
Daily Flip
Your best move
Invite someone to beat your distance. The challenge opens the original puzzle with your answer hidden.
Keep a picture of this flip
This 1200 × 630 PNG shows your reading, target, move, and answer. It is created in your browser. A picture reveals the solution; send the blind puzzle link above if you want someone to solve it first. Use invented or public data in a shared puzzle.
One fresh case each calendar day
The daily flip.
Every visitor opening the same date sees the same generated arrangement. Your best successful move stays on this device.
Seven dates · seven exact puzzles
Your seven-day trail.
Revisit a date or pick up where you left off. Gold marks a saved exact minimum on this device.
Explore another date.
Choose today or an earlier date from 2000 onward. Each date generates the same puzzle on every device.
999,999 numbered cases / exact reversals
The open run.
Keep playing generated reversals. Each numbered case has its own reproducible link, and the next case unlocks after a strict flip. Practice has no saved score; daily progress stays its own thing.
Three different reversals
Choose a round.
Each arrangement has a strict reversal. Your best move and attempts stay on this page for the current puzzle only.
Pass the puzzle on
See who can beat your move.
The link opens the same starting arrangement, with the solution hidden. It does not include your guesses or score.
“Shortest” means the least change to a single reading on a four-decimal grid in 0–100 that produces the opposing strict winner. A tie is not a reversal. The target and cases are invented what-if inputs, not measured truth. The daily date is taken from your device's local calendar when you open “today”; its resulting dated URL reproduces the same case worldwide. Shared custom puzzle URLs contain all five readings and the target; use invented or public values. No account or leaderboard; daily bests use this device's local storage only when available.