A calm sorting game. The vials hold layers of colour in a jumble, and the job is to put them in order: every vial must end up either empty or filled with a single colour. One click picks the vial to pour from, a second says where to. You can pour into an empty vial or onto a matching top layer, and the whole top run of one colour moves at once, as much of it as fits.
Two habits keep a puzzle out of deadlock. First, make the pours that join two runs of the same colour: they never need undoing, and each one is a step towards the end. Second, keep an empty vial for as long as you can. An empty vial is the only move left when no two tops match, and spending one on a single layer is the most common way a puzzle dies.