Everyone loves a quiz now and then, but the budding vexilologists among us are only sated by a good old flag quiz! The World Flags Quiz Slide Puzzle app combines knowledge of flags with sliding puzzles, where you have to move tiles around until you complete an image, like a jigsaw. There are trivia questions after each puzzle and four levels of difficulty for each one, adding new dimensions to the game. This free game is easy to use, as sliding puzzles are perfect for touch controls.