8.14: Using Movement Variables to Handle User Input

                elif (event.key == K_LEFT or event.key == K_a):
                    movingLeft = False
                elif (event.key == K_RIGHT or event.key == K_d):
                    movingRight = False
                elif (event.key == K_DOWN or event.key == K_s):
                    movingDown = False

Letting up on one of the arrow keys (or the WASD keys) will set the movingLeft, movingRight, or movingDown variables back to False, indicating that the player no longer wants to move the piece in those directions. The code later will handle what to do based on the Boolean values inside these "moving" variables. Note that the up arrow and W keys are used for rotating the piece, not moving the piece up. This is why there is no movingUp variable.

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