Einstein Challenge is a tick and cross logic puzzle game to challenge your brain. This type of logic puzzle doesnt have an official name, each player calls it a different name, such as Logic Problems, Logic Elimination or Zebra Puzzle. • Thousands of Riddles: 5000 logic puzzles, all free! No packs to buy. • Daily Challenges: 15 free unique daily challenges. • Increasing Difficulty: Several grid sizes, from 4x4 to 16x9 - the bigger the harder. • Filters for Experts: Filters to help you find hints