code2flow.source

start:
Create empty board;
Add random tile;
game_loop:
Draw board;
Read user input;
switch (key) {
  case Q:
    exit;
    return
    break;
  case R:
    goto start;
  case ←,↑,→,↓:
    Make move on board;
}

if (Board changed?) {
  if (Board contains 2048?) {
    Draw win screen;
    goto start;
  }
  Add random tile;
  if (Board is full?) {
    Draw game over;
    goto start;
  }
}
goto game_loop;