Ask out loud · watch it happen
You describe it.
Cog goes and builds it.
Not a menu. Not a template you fill in. You say what you want in your own words, and someone gets on with it while you stand there and watch the blocks go down.
And when what you want is not a thing but a game — a goal that counts, a timer that runs, a hill worth standing on — they write new rules and load them into the world you are in. Both are below. Every model on this page turns; take hold of one and have a look round it.
YouBuild me a house shaped like SpongeBob SquarePants, and I want to go inside it.
Nobody put a SpongeBob in the cupboard for them
This is the one that used to be impossible. There is no sponge-house builder and there never will be — nobody can stock every idea a nine-year-old is going to have. So they worked the whole thing out from the sentence: the square yellow body, the holes right through it, round eyes, buck teeth, freckles, the white shirt and brown trousers. Then they hollowed him out and put a bed and a table inside.
24,688 blocks placed · 24,688 correct · 0 wrong · and Cog walkeds in, 14 blocks past the wall
This is the real design, cell for cell — the same one that went into the world.
YouA pirate galleon out on the open sea.
Ninety-six blocks of ship, and it took their six goes
A dark timber hull sitting down in the water with white foam breaking at the bow. Two gun decks with the cannons run out, a raised stern castle with windows in it, three masts, rigging, a bowsprit, and the skull and crossbones at the masthead. Cog’s first go was a model boat in a bathtub — the sea was a tray that stopped at the hull. Cog widened the sea to the full ninety-six blocks, dropped the ship down into it, and put the foam where the water breaks.
30,263 blocks · one solid piece, nothing floating · 13,000 of them are sea, and it moves
YouA rocket on its launch pad, ready to fly.
The fins took their four goes, and they knew it
A nose cone that tapers properly, fins standing off the hull with daylight between them, an engine bell underneath with the glow inside it, and a gantry alongside with walkways and floodlights. Cog’s first draft had the fins fused into one solid skirt. Nobody told them to fix that — they looked at it, did not like it either, and rebuilt them.
22,035 blocks placed · 22,035 correct · 0 wrong · up in five seconds
YouCut a canyon through here, run a river down it, and put a village on the floor.
A gorge, a waterfall, and a village at the bottom of it
Cog cuts the ravine, stepped the walls back in shelves so they read like real rock instead of a trench, and sent a waterfall over the rim into a plunge pool. Then they put six houses along the water and ran a path between the doors.
Watch it build itself. This is the actual shape they cut.
YouI want to get across the lake.
Three hundred blocks of open water, crossed
Cog pickeds the line themselves, raised the deck clear of the surface so it reads as a bridge and not a causeway, laid cobble on the approaches and planks over the water, and railed both sides. Then they walked it end to end to prove it.
940 deck blocks · one unbroken span · no gaps, no steps too big to walk
YouBuild me a rollercoaster. A real one I can ride.
Get in. It actually goes
A full loop of track with a hill in it, powered rails so you keep your speed, timber trestles holding it up and a cart waiting at the station. Every rail is laid with the right shape through the curves and the climb — get one wrong and the cart leaves the track at the first bend.
132 track cells, every shape correct · 28 boosters live · a cart rode 55 blocks in 10 seconds and took the whole hill
YouPut a secret door in this wall. Nobody should be able to tell.
A wall that opens, made of real redstone
Sticky pistons, wire, and a lever — built block by block, the way you would build it yourself. Flip the lever and a solid wall slides across the doorway. Flip it back and the doorway is simply there again.
Verified at 2, 4 and 6 blocks wide · opens, seals, and does it again every time
YouA watchtower. Tall enough to see the whole valley.
Five floors and a staircase that actually goes up
Windows on every floor, battlements around the top, and a spiral stair inside that rises exactly one block a step — so you can genuinely climb it rather than looking at it.
YouAn arena for me and my mates. Make it fair.
Fair at both ends, down to the block
Walled and lit, with cover through the middle to break the sight lines, and two spawn platforms mirrored end to end. Neither side gets the better half, because the layout is symmetric by construction.
YouBuild us a castle. A proper one, with walls we can stand on.
One way in, and it is the gate
Curtain walls with a rampart walk along the top, a tower on each corner, a hall in the courtyard and a gatehouse you walk straight through. Then they checked it was actually sealed — every route in and out, from the inside.
Enclosed, proved: 1,721 places you can stand inside · 0 ways out with the gate shut
YouPut a lake in, with a beach round it.
Water that stays where they put it
Cog digs the basin, shelves the edges so it shallows out instead of dropping away, lays a sand shore round it and fills it to one flat level. Then they come back and count it, because water is the one thing that leaves if you let it.
667 blocks of water placed · 667 still there half a minute later · none outside the basin
YouBuild me a pyramid I can actually walk inside.
Not a pile of blocks — a building
Stepped stone with the courses banded so it catches the light, a lit passage in from the north face, and a chamber at the heart of it tall enough to stand up in.
The bit a photograph cannot show you
Take the front off and have a look inside
"You can walk into it" is the one thing about a build you cannot settle by looking at it, and measuring the air inside does not settle it either — the space between a statue's legs measures the same as a room. So they walk in. Cog got 14 blocks past the wall of this house, on foot, with the same physics as anybody else. Here is the same house with the furniture in it. Drag the slider and the front wall comes away a course at a time.
the whole house, 33 blocks deep
Nothing was waiting in a cupboard
Ask for something else and they design that instead
No sponge library, no dragon template. Each of these started as one sentence and went through the same loop: draft it three ways at once, keep the soundest, look at what they drew from the front, the side and above, say what is wrong with it, and draw it again. The chess knight took one draft and two and a half minutes. The treehouse took eighteen, and came back with lit windows.
All four are standing in a world right now. Between them that is 119,560 blocks placed, and every one of them was read back out of the world block by block afterwards: 119,560 right, 0 wrong.
YouA treehouse village: three timber huts up in a giant oak, joined by rope bridges, with ladders down to the ground.
- 35,252 blocks
- 75 x 83 x 53 — width, height, depth
- 2.5 seconds to place, standing at 483, -386
- 35,252 of 35,252 read back out of the world afterwards, 0 wrong
- they walked inside it — 22 blocks in from the outside, under 26 blocks of it
YouA lighthouse on a rocky headland, white with a red band and a glowing lamp room at the top.
- 29,270 blocks
- 48 x 81 x 48 — width, height, depth
- 1.5 seconds to place, standing at -384, -324
- 29,270 of 29,270 read back out of the world afterwards, 0 wrong
- they walked inside it — 13 blocks in from the outside, under 3 blocks of it
YouA giant chess knight.
- 18,508 blocks
- 31 x 71 x 38 — width, height, depth
- 0.9 seconds to place, standing at 185, -439
- 18,508 of 18,508 read back out of the world afterwards, 0 wrong
- they walked inside it — 11 blocks in from the outside, under 16 blocks of it
YouA huge stone dragon curled around a rocky outcrop, wings folded, head raised and mouth open.
- 36,530 blocks
- 56 x 62 x 70 — width, height, depth
- 3.0 seconds to place, standing at 532, 265
- 36,530 of 36,530 read back out of the world afterwards, 0 wrong
- no way in — they went and tried, and could not find a route to anywhere inside it
The other half
And then they change the rules of the game.
Everything above is something you look at. This is something that happens back. Ask for a game and Cog does not build you a field and leave you to it — they write new rules, loads them into the server while everyone is still standing in it, and then plays every one of them themselves to check they fire.
GOAL
Click the pitch to take a shot
YouA soccer pitch with two goals, snowballs for balls, first to five wins, and it shouts when someone scores.
Nine rules, written and running in 1.5 seconds
Cog laid the pitch — markings, centre circle, goal frames in red and blue glass, a pad at each end — and then wrote the rules that make it a game. Stand on your team's pad and it hands you snowballs and a bit of speed. Put one through the goal mouth and the score goes up, the whistle goes, and everyone gets told. First to five and the fireworks go off.
Nobody installed anything. No restart, nobody kicked, no plugin list. The server simply knew how to play soccer a second and a half after it did not.
9 rules · 5 regions · 37 pitch-laying steps · all 9 rules triggered on purpose, all 9 fired
The pitch and the goal boxes here are read out of the same file the server is running.
What it actually looks like
One sentence in the chat box
This is the whole exchange, copied out of a real world. Nothing between these two lines was typed by anyone.
Samcan you make us a spleef arena at 440,64,300? you stand on a floor and break the blocks under each other, last one standing wins
CogOn it! I'll get a spleef arena built at those coords — should take a few minutes. I'll let you know when it's ready to play!
they keep talking to everyone else while they work · 4 minutes 55 seconds
CogDone! Finished your Snow Spleef Arena — 10 rules, 5 regions, 15 datapack files, all 10 rules tested and firing.
Twelve seconds to answer, because answering is a different job to designing and runs on a different model. The arena, the rules and the testing took the rest. Cog’s first draft was rejected by their own compiler for a message that was too long to fit on screen; they fixed it and carried on without mentioning it.
6 they wrote in one evening
Six games nobody had to install.
Every one of these started as a single sentence. Cog laid the pitch, wrote the rules, and put them into the world people were already standing in — no restart, nobody kicked off, nothing to download. Then they went and set off every rule themselves to check it fired: dropping a snowball into the goal, winding the clock to the tick a timer waits for, standing on the pads. All 67 of them, and all 67 worked. Pick one and have a look at the ground it is played on.
YouA soccer pitch with two goals, snowballs for balls, first to five wins.
- 9 rules
- 5 regions watched every tick
- 37 steps to lay the arena
- 1,641 ms to go live
- 9/9 testable rules triggered and firing
YouAn arena match: two teams, a kit pad each, score when you tag someone in their base, first to ten.
- 14 rules
- 6 regions watched every tick
- 34 steps to lay the arena
- 1,485 ms to go live
- 14/14 testable rules triggered and firing
YouA shooting range where the targets light up and score when you hit them.
- 11 rules
- 7 regions watched every tick
- 31 steps to lay the arena
- 1,538 ms to go live
- 11/11 testable rules triggered and firing
YouKing of the hill — you score for every second your team holds the top alone.
- 14 rules
- 5 regions watched every tick
- 27 steps to lay the arena
- 1,414 ms to go live
- 14/14 testable rules triggered and firing
YouA sprint race with a countdown, a clock, and a finish line that stops it.
- 12 rules
- 4 regions watched every tick
- 30 steps to lay the arena
- 1,523 ms to go live
- 12/12 testable rules triggered and firing
YouA parkour course with a timer and a finish pad that shouts your time.
- 7 rules
- 4 regions watched every tick
- 21 steps to lay the arena
- 1,515 ms to go live
- 7/7 testable rules triggered and firing
The arenas above are drawn from the same files the server is running, and every number beside them was read back off it. Cog stands in their own start pads and finish lines to check those fire too — they are a player, so there is no rule left that nobody tried.
Whatever you ask for next, it gets built the same way.
One world, always on, with a builder in it who knows what they are doing. Tell it what you want when the idea turns up — not when you have a weekend free.
Be in the first worlds.
We are opening a small number to begin with. Put your name down and we will tell you when yours is ready.