Abacus 3D

Take the classroom abacus and turn its beads into a puzzle: instead of counting, you're sliding same-colored pieces into a straight vertical line to clear them and score. Early levels are really just a tutorial in disguise, walking you through the movement before the real difficulty shows up. Once it ramps up, you have to plan a few moves ahead rather than grabbing the nearest matching piece, since one careless slide can block a line you needed. The 3D framing is a novelty on top of what's otherwise a tight little logic puzzle.