Circuit
Two to four karts on a track drawn from the seed, seen from above. One key steers left, one steers right, and the throttle looks after itself: the kart is always accelerating unless you are braking. Three laps, and the first one home wins.
The track
- Every race gets its own track, drawn from the seed the match was made with. Nobody has driven it before, and both players are seeing it for the first time.
- It is a closed loop of ninety-six segments with corners of every kind on it: long curves, chicanes and at least one that has to be taken slowly.
- The track is eight cells wide from edge to edge. There is no grass and no run-off: the edge is a wall.
- Touching the wall costs you speed rather than the race. The kart is put back on the track and half the speed it hit with is taken off it, which on a tight corner is most of a straight's worth of work.
- The whole track is drawn on the minimap in the corner, with every kart on it. Tap or click the minimap to look at another part of the track, and press R, or the button under the track, to go back to your own kart.
The race
- Everybody starts on a grid behind the line, two abreast, and who gets pole is drawn from the seed.
- Three seconds of countdown, then green. Nothing moves before green.
- Steer with the left and right arrows, or A and D. On a phone, the left half of the track steers left and the right half steers right.
- Both directions at once is the brake, and so is the down arrow, S, or the third button on the pad. There is no separate throttle: let go of everything and the kart drives itself forward.
- Turning hard at speed makes the back step out. A kart that is sliding is quicker into a corner and slower out of it, and it leaves marks on the tarmac so everybody can see it happen.
- Karts bump. A kart you hit is pushed, and so are you, so a dive up the inside costs you both something and is sometimes worth it anyway.
- The race is run fifty times a second on the server, and the server decides where every kart is. Your own kart is drawn a moment ahead of the last thing the server said, so the steering answers the frame you pressed it in.
How a race ends
- Three laps. The first kart home wins, and the rest are placed in the order they finish.
- A lap only counts if you have been most of the way round: you cannot wiggle back and forth over the start line and collect laps.
- A race that has taken five minutes is over where it stands, and the karts are placed by how far round they are. Two minutes is a normal race, so the cap is only reached by a kart that is not being driven at all.
- A player who resigns is out of the race. At two players the other one wins; at three or four the race is started again from the grid for the players left.
- Everybody is steering the whole time, so the site's move deadline of five minutes is only a dead man's switch: if nothing at all happens for that long the match is abandoned and nobody is rated.
- A player who drops out is covered by the bot within half a second and gets their kart back the moment they return. Somebody who is away for more than half the race forfeits their seat; somebody whose phone dropped for a few seconds keeps their result.
Worth knowing before you start
- Circuit needs a live connection. If your browser or network cannot open one the page says so rather than offering a race that cannot be steered.
- If the player whose machine is holding the race drops out, the race starts again from the grid on another machine and the page says so. There is one race in a match, so there is nothing else to lose.
- The camera looks ahead of your kart rather than straight down at it, which is what makes a corner arrive in time to be taken. Press H to turn the world with the kart instead of keeping north up.
- Nothing is hidden. Every kart is on the screen, the track is the same for everybody, and the bot is reading the same picture you are.
- The bot drives at one of three strengths, drawn per match from the seed. The weakest one looks a long way ahead, which sounds clever and means it cuts corners into the wall; the strongest looks just ahead of itself and brakes for the tight ones.
- The race is stored as the steering that made it, so a finished match can be replayed and checked from its log.
Karts touch, so no kart is a pure function of its own driver and no page can safely predict anybody else. This one predicts your own kart with the same simulation the server is running and draws every other kart between the last two things the server said, which is why your steering feels immediate and a rival never slides through a corner they did not take.
Circuit terms
- A lap
- Once round the track, crossing the start line the right way. Three of them is a race. Going backwards over the line takes one off again.
- The grid
- Where the karts start, two abreast behind the line. Which slot you take is drawn from the seed, so nobody always starts on pole.
- A drift
- The back stepping out in a corner. It carries you in faster and costs you speed on the way out, and the tarmac shows where it happened.
- The cap
- Five minutes. A race still running then is stopped and the karts are placed by how far round they are. A driven kart never reaches it.