A sandbox game with logic gates, memory and radio — and machines that never stop

Is there a sandbox game with logic gates?

Yes — and this one runs on a whole planet. Openworld is a voxel sandbox game with logic gates built in: switches, relays, sensors, AND, OR, NOT, NAND, NOR and XOR gates, delays, memory and radios that you wire together with real cables. It's set on a round planet — walk straight and you come back to where you started — under a real sky, all the way to the Sun, and it runs natively on Mac (Apple Silicon), Windows and Linux.

What sets it apart from a circuit puzzle is that your circuits do something in a living world. They light a house at dusk, open a door when a friend walks up, warn you before a tank overflows, or carry a message across the planet by radio. And they run inside the OVM — the Openworld Virtual Machine — which keeps simulating them while you're far away.

• 256values on a signal cable, 0 to 255
• 128the level where a signal counts as on
• 50milliseconds: one turn, added by each logic part
• 256radio channels

Is it logic gates, or coding?

Mostly logic gates. Players combine switches, inverters and memory latches into AND, OR, NOT circuits and even whole computers. It feels like coding because you design a behaviour, but you never write a line: you build it piece by piece, like an electrician.

Circuits stay hands-on, with simple rules. A signal is a number from 0 to 255, not just on or off: it can mean "full", "half" or "a little" — and it counts as on from 128. Logic parts answer 255 or 0, and each one adds one turn of 50 ms, so a signal visibly travels through your build. And signals and power are two different things: logic travels on thin signal cables, while the energy that lights a lamp or turns a motor has to be produced and carried on power cables. The whole energy side is in our electricity and radio guide — here we stay on the logic.

So it's not a programming game?

No code, no scripts. Every behaviour comes from parts placed in the world and the cables between them. If you want a game where you program robots line by line, this isn't it. If you like to watch a circuit work with your own eyes — and walk inside it — it is.

The pieces: what sends a signal, what listens

Every device has ports: green for what comes in, orange for what goes out, lit up when you hold a cable — and each one now shows a small tag with its name and direction ("Input A · Input", "Write", "Channel 3"); F1 hides them. Right-click a device with an empty hand and its sheet explains, in simple words, arrows and real numbers ("180 × 100 ÷ 255 = 71"), what it does and what it's doing right now.

What sends a signal

• Light switch and button: 255 while on — or the value you set on the switch's sheet, from 0 to 255 (a switch set to 1 is a "+1", one set to 100 a "×100"). A button stays pressed for one second.
• Presence sensor: 255 while a player or a creature stands in front of it (radius 1 to 8 m), held a few seconds after they leave. It needs a little power to watch.
• Level sensor: set against a tank, it tells how full it is, from 0 to 255. Powered too.
• Chunk sensor: 255 while the land around it is loaded and settled.
• The battery reports its charge, the solar panel what it's giving, the generator whether it runs, and a receiving antenna what it hears.

What listens

• Electric relay: closes a power line when its command reaches 128, half the scale. It draws 2 W while closed.
• Transistor: lets through a share of the current that follows the signal — signal ÷ 255. It's your dimmer: a lamp behind it shines in quarters.
• Valve: opens a pipe by hand, or on command in proportion to the signal (20 W). The tap next to it simply fills your bucket.
• Doors and trapdoors on a signal cable open at 128 and fall shut below.
• Lamps, machines, motors and pumps stop when their command drops to 0, and a motor's speed follows its command.
• Junction: splits a cable. On a signal cable it copies the signal to every branch.

The logic components (new in alpha 1.0.9)

• Delay: gives back what it received N turns ago — from 1 to 600 turns, 0.05 to 30 seconds, 0.5 s by default.
• Logic gate: AND, OR, NOT, NAND, NOR or XOR, chosen on its sheet. NAND and NOR are AND and OR turned upside down; XOR is on when exactly one input is. It works bit by bit on the signal's 8 bits (NOT gives 255 − A); with signals at 0 or 255, it's the classic gate.
• Op-amp: adds (capped at 255), subtracts (never below 0), does the rule of three A × B ÷ C (leave C unplugged and it's 255: a percentage), or compares A > B and A = B.
• Memory: on the rising edge of its Write input, it copies Value and keeps it — a D flip-flop, 0 at the start.
• Optical coupler: eight signal channels on one side, a fibre on the other. As a laser it sends them down the fibre, as a photocell it reads them back. It needs 5 W.
• Display panel: the large wall sign, with four command inputs. In its text, {1} to {4} become live values — "Battery: {1} %" — on 1 W of power.

Logic components need no power cable: the signal cable that links them feeds them. Only the coupler and the display panel want a small power cable. Each one is a small iron-bound oak box whose setting is engraved in brass on top and in front — "0.5s", "AND", "A+B", "A*B/C", ">", "MEM", "TX" / "RX" — with a glass lamp that lights while its output is on. The older devices engrave theirs too: an antenna's "CH 7", a valve's "AUTO", a presence sensor's "4m 2s". Every component is crafted in the grid, from the Technology branch of the recipe book.

To carry signals, the signal cable reaches 256 m, an optical fibre 10 km, and an octo fibre carries eight signals at once, one per colour. Farther than that, a repeater passes them on. These small cables are laid voxel by voxel (25 cm), along a wall or under a shelf, as neat as you like.

How to make logic gates in Openworld

Here are circuits that really work with today's parts. The old electrician's tricks still hold, and the new boxes open the rest. Try five of them in the scene below: click the switches and the button, change circuit, watch the pulses run — gold for power, red for signals.

• AND, OR, NOT, NAND, NOR, XOR — one box. Set a logic gate on its sheet and wire its inputs A and B. The electrician's way still works too: two relays in series make an AND, and two senders on one signal cable make an OR, because a cable always carries the highest signal put on it — that's how the house of /ovm demo home opens its front door from two presence sensors.
• Clock — a delay and a NOT, looped. The NOT turns the delay's output upside down and feeds it back in: the signal flips every half second, forever. Shorten the delay for a faster beat.
• Pulse. A signal AND the NOT of its own delayed copy: when a button goes on, you get one short pulse, as long as the delay.
• Counter. The button on the memory's Write; the memory's output into an op-amp set to Add, with a switch set to 1 on B; the sum back into the memory's Value. Each press adds one. Put the memory on a display panel and read "Count: 7".
• Toggle. A memory whose Value is the NOT of its own output, and a button on Write: each press flips it — one button for the hall light.
• Adjustable threshold. A relay closes at 128; for any other level, an op-amp set to ">" with a switch set to the value you want: "tank above 200".
• Battery in percent. An op-amp in A × B ÷ C, the battery's charge on A, a switch set to 100 on B, C unplugged: 255 becomes 100. On a display panel: "Battery: 71 %".
• Proportional — a dimmer. A level sensor on a transistor brightens a lamp as the tank fills, a quarter at a time; on a valve you get a flow that follows the level, on a motor a speed.
• An 8-lane bus. Eight signals into an optical coupler set to laser, an octo fibre up to 10 km, a coupler set to photocell at the other end: your whole control panel, far away.

Want them ready-made? In a creative world, /ovm demo logic builds four of them with their plaques: a clock blinking a lamp, the battery's percentage on a panel, a counter that climbs at each press, and three switches crossing a fibre between two couplers.

Click a switch, the button or a part

Machines that keep running when nobody is near

A circuit doesn't depend on a loaded chunk. Every device and every link is also registered in the OVM, which simulates them even where no chunk is loaded. Your sensors keep reading, your relays keep switching and your tank keeps filling while you explore the other side of the planet.

The OVM runs on its own thread, aiming for 20 turns a second, and each turn is always 50 ms of simulated time. Build something enormous and it's the OVM's pace that drops — everything slows down evenly, nothing is skipped — never the game's TPS: players, creatures and blocks keep their normal speed. A badge on screen tells you ("OVM 12 Hz (60 %)", orange under 90 %, red under 50 %), /ovm stats gives the details, and the F3 debug screen has an OVM card.

Distance costs almost nothing. A link is one channel with two ends, a length and a drop, so a cable across a valley or a pipeline around the planet costs the same as a short one; what costs is the number of devices. This is also what lets factories run while you're away: furnaces and conveyors live in the same simulation as your circuits.

/ovm stats
/ovm scope world
/ovm scope loaded

Radio: masts, and dishes that follow the Moon

Antennas carry a signal with no cable at all. There are 256 channels: an emitter sends its command (0 to 255) on its channel, and every antenna within reach listening on that channel puts what it hears on its own signal cable. Press a button at home, a lamp lights up in the next village.

• The omnidirectional mast talks all around: perfect for a valley or a village. It can't reach the Moon.
• The directional dish concentrates its beam in a 2° cone and carries much farther for the same power. Aim it through a spyglass view (×1 to ×32), or tell it to follow the Moon — or, from the Moon, the Earth — and it turns on its own as the planet spins.

Its sheet speaks plainly: pick a target — Nearby (100 m), Village (1 km), Region (10 km), Far (100 km), the Moon — and it tells you what it will consume. Range follows a real radio law (the Friis formula): reaching the Moon, 60,000 km away in the game, takes about 34 kW with a dish at each end.

And waves never go through the ground. A hill between two masts, the curve of the round planet, or the Earth itself when the Moon sets: the link is cut. A dish whose target sinks below the horizon goes quiet ("Target below the horizon") until it rises again. Type /radio show-signal true to see the beams.

Gears, transformers and the signal writer

Gears with the ratio you choose

Motion is part of the toolbox too. An electric motor turns a shaft at 120 rpm, and on that shaft you place your own gear wheels — small (1 m), medium (3 m) or large (5 m), in wood, iron or steel. Two gears side by side at the right distance mesh on their own: the ratio is the ratio of their sizes, and the direction flips. Chain them to get the speed you need. Energy is conserved — each mesh loses a little — and a contradictory train simply jams.

Transformers

Power travels in two sizes of cable: the small power cable (10 kW) and the large power cable (250 kW). A transformer joins the two, up or down, at 97 %: up to cross a valley, down again at home. All of it is in the electricity guide.

The signal writer: a recorder on paper

To see what your signals do over time, there's the signal writer, a desk chart recorder. Give it paper and a little power (15 W), plug in a signal cable — or an octo fibre, and eight pens draw eight channels in their colours. Choose its speed, from 20 points a second to one a minute. Each sheet holds 128 points and becomes a chart you read like a paper card; the writer keeps 16 of them in order — a whole night in the life of a sensor.

1. 1

   Power

   A solar panel or a generator, and a small power cable running to the corner of your tank.

2. 2

   The sensor

   Set a level sensor against the tank and feed it from that cable: it needs 3 W to read.

3. 3

   The relay

   Run a signal cable from the sensor to an electric relay on a lamp's power line. Above half full, the lamp lights.

4. 4

   The record

   Add a junction on the signal cable and a signal writer with paper: in the morning, the chart shows the level all night long.

Circuits that run a world

You can build computers with parts you can read at a glance, but the circuits are first made to run a world: houses, pumps, workshops and radio links that keep working across a whole planet — and that your friends see light up too, on Mac, PC or Linux.

What's coming next

The OVM is young: it arrived in October 2026, the logic components came with alpha 1.0.9, and it's still being reworked during the alpha, so exact figures may change — each device's sheet always shows the current ones. The display panel only shows numbers in decimal for now. Next on the list are antennas that go to space: relay antennas in orbit and satellites that pass a signal from one side of the planet to the other, or up to a station. They aren't in the game yet. Today you can already fly a rocket to orbit and build your own space station up there; the radio that will tie them together is planned.