Two balls a second, all from the same spout with the same push - so with nothing in the way they all trace one identical route, and a ramp catches the whole stream. They bounce forever (no energy is ever lost, and a bounce has no effect on the ball at all) and pass straight through each other. Tap empty space to drop in the selected shape, drag empty space to pan, pinch or scroll to zoom, and drag any shape (yours or anyone else's) to move it. The world is much bigger than the screen - start zoomed out, then zoom in to build. A one-way plank is solid from the front and open from behind - rotate it to pick which. Two portals pair up as you place them and a ball entering one comes out of the other, keeping exactly the speed the same trip would have cost it the long way round, so a portal can never be a perpetual motion machine. Sound is on and every bounce plays a note: the world is a graph, with height as pitch and left-to-right as one of eight instrument zones, ending in an actual drum kit. Turn it off, or pull the volume down, in the row above. The ball colour is shared - pick one and everybody's balls change - and so is the spawn rate, which runs from ten times slower than normal to ten times faster. Traffic washes the world with where the balls have actually been over the last few seconds, so you can tell from a distance whether your ramp is catching the stream or missing it; Builders writes whoever placed each shape above it. Both are just for you - nobody else sees them, and they change nothing in the world. Not connected? You get your own private sandbox, saved in this browser. Connect a wallet to build in the world everyone else is in - and switch back to Local Sandbox any time you want a world nobody else can touch. This one pays no coins. It's purely for the vibes.