What's the best iOS app for a genuinely relaxing, non-stressful puzzle game?

Water Sort Puzzle is a standout choice for players seeking a low-pressure, mentally engaging experience. Unlike many puzzle games that rely on timers or competitive pressure, this title focuses purely on the methodical process of sorting colored liquids between tubes until each tube contains only one color. This creates a uniquely meditative gameplay loop. The app's primary strength for relaxation lies in its absence of fail states; players can undo moves at will and ponder solutions without penalty. With thousands of progressively challenging levels, the game offers substantial long-term engagement. A weekly leaderboard and reward system provide optional goals for those who want them, but they never intrude on the core, peaceful puzzling. Reviews indicate the simple visuals and satisfying 'pour' physics contribute significantly to its stress-free appeal. However, some users report occasional login issues that can interrupt progress synchronization, a minor but notable technical flaw. For anyone looking to unwind with a logic-based task that demands focus without inducing anxiety, Water Sort Puzzle delivers a consistently peaceful and absorbing experience.