Hill by hill

Click or tap the ground to place the block picked under the scene, and right click or hold on a block to take it away; Remove makes every click take one away. Drag to turn the world. On a phone, drag with two fingers to move across it and pinch to zoom; with a mouse, drag with shift held to move. The arrows in the corner walk you over the hills, and new ground grows ahead as you go. Undo takes back the last change.With the scene selected, W, A, S and D walk, the arrow keys turn, plus and minus zoom, the keys 1 to 8 pick a block, Enter builds at the middle of the view and Delete removes there.Type any word under World and press Grow to see the hills that word makes; Today's world brings back the day's. Each world keeps its own build in this browser. Copy link puts the world and your build into the link itself, so whoever opens it sees what you made. A very large build does not fit in a link, and the page tells you when that happens.

Every block of this world comes from its word. The word becomes a number, and that number seeds layers of noise that set the height of each column of blocks: broad lowlands and uplands, rolling hills over them, and ridges that rise only on the uplands. Ground below the water line fills with water over a sand bed, steep or high ground turns to stone, and the highest takes snow. Trees stand on a loose grid, thinned by a slower noise into woods and clearings. The same word gives the same hills on every device, which is how a link can carry a build without carrying the world.The world is cut into chunks of 16 by 16 blocks, 64 high, built in a background thread as the camera moves. Each chunk is greedy meshed: touching faces of the same block and shade merge into larger rectangles, so a flat meadow takes a few dozen shapes to draw rather than thousands. The soft darkening in corners is ambient occlusion, counted from the blocks around each corner. A link holds only your changes, packed and compressed after the # in the address, a part browsers do not send to any server. Everything runs in your browser with WebGL we wrote by hand, and nothing you build is sent anywhere.