4x4 Grid Electronic Sudoku Toy A compact, portable electronic Sudoku device that delivers progressive logic challenges for players of all levels. The device uses a 4x4 grid format with 3500 preset levels ranging from beginner to expert. Real time feedback helps players spot and correct mistakes as they play. Key features and benefits Progressive difficulty: 3500 levels provide a clear learning path from simple puzzles to complex challenges, keeping players engaged over time. Targeted brain training: Regular use supports memory, early math skills, critical thinking, logic, and problem solving through structured puzzle practice. Instant feedback: Error notifications during play speed learning and reinforce correct logical approaches without interrupting the game flow. Portable and compact: Small enough to slip into a bag for travel or to carry to school, work, or outings for puzzle time anywhere. Simple, focused functionality: Electronic interface designed for easy operation and quick game setup so players can start puzzles quickly. What makes it useful Solves the need for accessible, bite sized logic practice by combining many difficulty levels in one handheld device. Removes the need to carry puzzle books or printouts by providing a reusable, electronic solution. Helps learners practice structured thinking and problem solving without time consuming setup. Typical use scenarios Travel companion: Keep children occupied and mentally engaged on long journeys or during waiting times. Classroom or study hall: Use as a quiet activity to reinforce logic and early math skills outside formal lessons. Short daily practice: Use a brief session before or after school to build consistent logic practice and focus. Specifications and function Grid format: 4 by 4 Sudoku puzzles. Levels: 3500 preset puzzles covering beginner through expert difficulty. Feedback: Real time error notification during gameplay. Design: Compact electronic device intended for portable use and easy storage. This device is a practical tool for parents, educators, and puzzle enthusiasts who want a portable, progressive Sudoku experience that supports logical thinking and early math practice.