About Rusher or Dragger
What Is It?
It's based on the scene in Whiplash where Fletcher stops the band to ask: were you rushing or were you dragging? A metronome clicks at a random tempo between 120 and 180 beats per minute. Tap along, and after eight clicks it goes quiet. Keep the tempo going on your own for about ten seconds, until the click comes back in right where it would have been if it had never stopped. Then you find out which you were.
How to Play
Tap the box, click it, or press the space bar. The first tap starts the click, and it keeps going for as long as you like, so take your time getting the feel of it. Once you start tapping along, it counts down eight more clicks, from 8 to 1, and stops. Keep tapping through the quiet. When the click comes back in, it plays eight more so you can hear how far you drifted, and then your score comes up.
Scoring
Only the taps during the quiet part count. Time 0 is the last click before the quiet, the one counted 1, and a tap less than half a beat after it still belongs to that click, so it isn't counted. The quiet lasts the whole number of beats closest to ten seconds, so the click comes back in on a beat.
Your tempo is the number of taps you made in the quiet over the time of the last one. 29 taps with the last at 9.9 seconds is 29 / 9.9 × 60 = 175.8 bpm. Your score is how far that is from the click's tempo: plus for rushing, minus for dragging. Closer to 0 is better. Underneath, it also says how far ahead of or behind the beat your last tap landed, which is the drift you hear when the click comes back.
Lining Up
Nobody taps exactly on the click. Most people tap a little ahead of it, and phones and computers take a moment to get a sound out of the speaker and to notice a tap. So time 0 isn't when the last click played, but when you would have tapped it. Your taps along with the eight clicks show how far ahead of or behind the click you tap, and time 0 is moved by the middle of those. That way, tapping a hair early on every beat doesn't count as rushing.
Not Counted
A round isn't scored if two taps are less than half a beat apart (one beat tapped twice) or more than a beat and a half apart (a beat skipped), or if you stop before the click comes back. The tempo comes from counting taps, so one extra or one missing would throw it off by several bpm.
The Graph
Across is time, from 0 until the click came back. Up is rushing and down is dragging, in bpm. Each dot is one beat: the tempo of the gap before that tap, on its own. With a 60 bpm click, a tap 0.9 seconds after the one before is 1 / 0.9 × 60 = 66.7 bpm, so its dot goes at +6.7. A dot too far off to fit is pinned to the edge as a ring.
Single gaps jump around a lot, since a tap a hundredth of a second off moves its dot by several bpm. So the line is smoothed: at each moment, it averages the gaps around it, with nearer ones counting more and most of the weight within about a second either way, and turns that into a tempo. The dashed line is your score. Hover over the graph, or drag a finger along it, to read off any beat.
Cheating
Once you've had a round scored for real, a cheat switch shows up next to your best score. With it on, the click keeps going through the quiet, so you can hear what you should have been doing, or see what the scoring makes of you when you're right with the click. Cheating rounds are scored and graphed as usual, but never count as your best. The switch starts off each time you open the game, and can't be flipped in the middle of a round.
Best Score
Your best score, the one closest to 0, is shown above the box and is saved in your browser, so it sticks around between visits. The button below erases it, and puts the cheat switch away again until you've had another round scored for real. It asks first, because this can't be undone.