Flow Dots: Connect the Pipe

Pairs of coloured dots sit on a grid. Drag from one dot to its partner and a pipe follows your finger.

Two things have to be true at the end, not one: every pair joined, and every cell carrying pipe. Joining all the pairs while leaving a hole in the corner is not a solution — and that second condition is the whole puzzle. The short route between two dots is almost never the right one, because something else needed the space it saved.

Drag across a pipe that is already there and it cuts back to where you crossed it. Drag back along your own and it rubs out. The board is a sketchpad, so a wrong line is drawn through rather than hunted down and undone.

Every board is built backwards: the grid is cut into paths first and the dots are placed at their ends, so a level can always be packed exactly. There is never a board that merely looks solvable.

No timer, no lives, no way to lose. Boards grow from five squares a side to nine, and from four pairs to eight. Each pair's dots carry a ring pattern as well as a colour, so two pipes are never told apart by hue alone. Works offline, and there is a new board every day.