Collect 21 app for iPhone and iPad
Playing Collect 21 for 10 minutes a day sharpens your mind and prepares you for your daily life and challenges!
Collect numbers - Challenge your brain through thousands of mahjong puzzles. Puzzles start with low difficulty and become challenging fast!
Create a Calm Experience - Solve addictive yet always evolving numbers by collecting mahjong puzzles in a unique and calm experience.