The main loop is quite simple. In each frame we draw everything. Later, we use keyboard input in order to move the piece. Before each movement, we first check out if it is possible. We also measure the time in order to move the piece down every n milliseconds. When the piece fall down one block, we check out if that movement is possible, if not, we store the piece in the board. We also check out if there are blocks in the upper row, if so, the game is over.