Sorter: Build the Line

Sorter: Build the Line is not a sorting puzzle so much as a machine-building one. You lay out ramps and colour splitters on a grid, press Run, and then watch a flood of balls pour through whatever contraption you have built, hoping each one ends up in the right bin.

The distinction matters. In most sorting games you make the moves yourself, one at a time, and can correct course as you go. Here you make every decision up front, and once the balls are pouring you only watch. You are not guessing, though: while you build, a thin line traces where each colour will go, so you can see a mistake before you press Run.

Splitters are the interesting component, sending colours in different directions and letting one path serve several bins. Ramps carry balls across the board. Between them you are solving a routing problem: every colour needs a continuous path from where it enters to the bin that wants it, and those paths share the same limited grid.

The failure mode that teaches the most is the near miss — a machine where three colours land perfectly and the fourth trickles into the wrong bin. That is usually one flipped piece away from working, and flipping a placed piece is a single tap.

Because Run is repeatable and nothing is lost by trying, the loop is quick: build, run, watch, adjust. Tap a palette piece then tap a grid cell to place it, and tap a placed piece to flip its direction. Runs in the browser on desktop and mobile with nothing to install.

The levels do not run out. The first uses a 3 by 4 grid, two colours and a single splitter; the hand-made climb ends on 7 by 8 grids with four colours, three ramps, three splitters and walls in the way, and after that new boards keep coming: one of those big machines, mirrored or recoloured, with an extra wall, never the same board twice in a row. The game remembers the furthest level you reached and opens there. Every ball drops from the same inlet at the top, and each level hands you a fixed set of pieces, shown with a count in the palette. You cannot get more, so the puzzle is making that exact kit do the job.

You are never building blind. While you work, a thin coloured line traces the path each colour would take right now, and every bin shows a tick or a cross. When all the bins show a tick, press Run and four balls of each colour pour through in a random order. If a run goes wrong you are back in build mode with nothing lost. The Erase tool takes a piece off the board and returns it to your stock, and Clear resets the whole level.