Briefly, the goal of the game is to randomly appear on the screen 9 pieces of myself. And I destroy them by stepping on them. It basically looks like a mole shooter game. I put gridlayout in ConstrainLayout as front-end. And I put 9 of my own images (ImageView) in it. Then I placed TextView on top and bottom. He was counting the 20-second time limit for each game above. The bottom one was the number of targets I hit. I will not describe the back-end so that it does not get unnecessarily long. But basically, it was a replayable game after 20 seconds were up.