How to play

One rule: paint every floor tile. One catch: the ball only stops when it hits something.

The goal

Each level is a small maze of floor tiles and walls with a ball resting on one of them. Every time the ball rolls over a floor tile, that tile is painted. Paint them all and the level is complete. There is no timer, so take as long as you like to think.

Controls

Phone or tablet: Swipe anywhere on the screen in the direction you want the ball to roll. You can keep your finger down and drag to chain several moves quickly.
Mouse: Click and drag in a direction, or flick. The same chaining works while the button is held.
Keyboard: Arrow keys or W, A, S, D to move. R restarts the level, H shows a hint for your next move, and Ctrl+Z (Cmd+Z on Mac) undoes the last move.

The ball keeps rolling in the chosen direction until it meets a wall or the edge of the board. You cannot stop it part way, so each move paints a whole line of tiles.

The tiles

Floor: the dark tiles. Roll over them to paint them. Painted tiles stay painted; rolling over them again is fine.
Walls: raised blocks the ball cannot enter. Use them to stop exactly where you want.
Corner arrows: turn the ball ninety degrees as it passes through, without stopping it. Enter from a closed side and the ball stops on the arrow instead.
Portals: come in pairs. Roll into one and the ball appears at its twin, still moving in the same direction.
Traps: hold the ball when it rolls in. Your next swipe breaks free. Traps count as painted once you have visited them.
Multiplier pads: split the ball into two or three balls that all obey your swipes at once. You finish when the whole board is painted, however many balls it took.
Pressure buttons: pressed when a ball rolls over them, they swap linked parts of the board between wall and floor for a few seconds.

Stars and the shop

Every level has a par: the fewest moves it can be solved in. Finishing earns stars, and finishing at or under par earns the most. Stars are spent in the shop, opened from the ball button at the top right, on ball skins and board themes. They are purely cosmetic and every level can be completed with the default set.

Tips

Find the tiles with one entrance first. A floor tile in a dead-end pocket can only be painted by rolling into it, and the ball will stop there. Those tiles decide the order of everything else.
Think in lines, not steps. Ask which long runs of unpainted tiles line up with a wall you can stop against.
Use corner arrows to change lanes. An arrow lets one swipe cover an L shape. Levels with arrows are usually asking you to find the single swipe that paints two edges at once.
Stuck? Undo, then hint. Undo is unlimited. The hint shows the next move of a known solution from where you are, so it never lies, though it may not match your own plan.
Restart is free. There is no penalty for starting a level over, and often a fresh look finds the route faster than repairing a messy one.

Want to know more about the game itself? Read the about page, or just start playing.