INTERNAL CLOCK · 15 ROUNDS
The timer disappears. Stop it when you think the target time has arrived.
Play 15 rounds. Every stop counts, and the smallest average error wins.
READY?
The running clock will vanish after a brief glimpse.
Keyboard: Space or Enter · Touch or mouse: tap the large STOP button.
HOW TO PLAY
Memorize the target duration shown at the top of the stage.
Watch the timer begin. It disappears after a short glimpse, but time keeps running.
Press Space or Enter, or tap STOP, when you believe the target time has arrived.
TIME ESTIMATION
The challenge combines attention, time estimation, and response control. Once the digits disappear, you must continue counting without a visual clock.
It is a casual browser game, not a clinical timing or attention assessment.
READ YOUR RESULT
Timing error is the absolute difference between your stop and the target. Stopping early and late by the same amount receive the same error.
Standard mode completes all 15 rounds. Endless mode tightens the tolerance after each hit and ends on the first miss or timeout.
QUESTIONS
The digits remain visible for a brief fixed glimpse at the start of every round, then change to question marks while the clock continues.
A hit means your absolute timing error is no greater than the displayed tolerance.
No. Early and late stops are measured by the same absolute error, so guessing in either direction hurts the result.
The tolerance bar becomes smaller after every hit. One miss or timeout ends the run.