Stop & Go

What is Stop & Go?

A camera-controlled take on Red Light / Green Light. A big traffic light cycles between green and red phases at random intervals. On green, any motion scores points (more for bigger bursts). On red, motion costs a life — with a tiny grace window right after the light turns red so you can freeze in time. Three lives, sixty-second round, tests impulse control more than aim.

The badge in Stop & Go

There is one badge here, kept on your own device and shown on the 🏆 Achievements panel on the home page. Nothing is sent anywhere and there is no account to make.

• Statue Master — Score 200 in Stop & Go.

How to play Stop & Go

1. Press Play now and allow the camera when the browser asks. Nothing installs.
2. Check what else is in shot. The referee watches the whole picture, not just you: someone walking past, a dog getting up, a television left on. All of it counts as your movement and takes a heart on red. Prop a phone or tablet up for the same reason — if the camera shifts, the whole picture changes at once and you are caught.
3. Wait out the 3-2-1. The round always opens on green, with a complete green phase ahead of you, so there is time to get going before the first red.
4. On green, move. Points land five or six times a second while you keep moving, and each one is worth more when more of you is moving. The whole score comes from here.
5. On red, stop everything. You get about a third of a second of grace after the light flips — enough to catch yourself mid-swing, not enough to finish the swing. Hands, head, feet, a bounce on your heels: all the same to the camera.

Sixty seconds and five hearts in the normal game. If the score will not climb on green, move more of you: a finger is under the line, a hand wave over it. If you never appear at all, the camera never started — the camera help page tests that in one click.

What counts as moving, and why red is stricter

The camera is not looking at your body. It compares each moment of the picture with the moment before and asks how much changed. Four things follow, and together they are what the game is made of.

• Red catches less than green pays for. The two levels are deliberately not the same: it takes slightly more movement to earn a point on green than to lose a heart on red. So there is a narrow band — a shifted foot, an arm drifting back down to your side — that scores nothing and still gets you caught. The freeze is judged harder than the go.
• Big movements pay more. A point lands roughly every fifth of a second while you move on green, and what each one is worth rises with how much of the picture is moving. A wrist wave earns the base rate; both arms out and off the floor earns a multiple of it. Over a round that gap is worth hundreds of points.
• You lose one heart at a time. After a heart goes there is a short pause before another can, so a wobble that carries on for a second costs one, not four. The screen flashes red as it happens, so you know which movement cost you.
• The light has no pattern to learn. Every green and every red is a fresh random length: green about two and a half to four seconds, red one and a half to two and a half. Counting it out does not work. The picture is tinted green or red as well as the light at the top, so you can watch yourself and still catch the flip.

Before two children try it together: as far as the camera is concerned, everyone in the picture is one player. One row of hearts, and movement anywhere spends it. That turns a competitive playground game into a cooperative one — whoever wobbles, you both pay.

What Hard mode changes

• Three hearts instead of five. Two fewer mistakes, in a game where one unlucky twitch is a mistake.
• Shorter greens, longer reds. Green drops to roughly a second and a half to three seconds, and red stretches to a second and a half to three. In the normal game you are free to move for about two thirds of the round; in hard it is nearer half.
• Smaller twitches get caught. The point at which red notices you is set lower, so a shift of weight, or a hand sinking back down after a big wave, takes a heart where normal would have let it go.

The two modes reward opposite things: normal rewards moving as much as you possibly can in the gaps, hard rewards being able to stop dead. Best scores are kept separately, and the Statue Master badge on the home screen — 200 points — takes whichever is higher.

Four ways to play it

• One at a time, taking turns. Scores compare cleanly this way: the same sixty seconds and the same hearts for everybody, with the light random for everybody too.
• Freeze in a shape. Agree on something first — a starfish, a tree, a robot — and hold every red in that shape. The game does not check it. The rest of the room does, which is the point.
• Sitting down, hands only. A hand wave is enough to score and enough to be caught, so the whole game works from a chair at a desk with the laptop where it already is.
• Chase the score, not the hearts. Move enormously on every green and accept an early finish. A short wild run and a careful full minute come out closer than you would think.

What a grown-up watching should know

A go is about a minute: three counted down, then sixty seconds, finishing sooner if the hearts run out. SPACE starts the next round, H goes back to the menu.

It makes noise on purpose. A backing track — brisk funk with a four-on-the-floor kick — plus a low note when the light turns red, a high one for green, and a rough buzz when a heart goes. M silences the track and leaves the notes, which is the setting you want: a child staring at their feet still hears the light change.

It needs no floor space. A cleared room and a chair at a desk are both real ways to play, because a hand counts as much as a whole body.

Nothing to read, nothing to aim at. The instruction is a coloured light and the only skill is stopping when told, which puts it well below reading age — while still being hard for an adult, because holding completely still for three seconds is not a children's difficulty. One caution: the screen flashes red when a heart is lost, no more than about once a second.

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