* how does bouncing works in bounce.c
** handling ball bounces relative to screen size
    use LINES and COLS to determine the values for BOT_ROW and RIGHT_EDGE

* responding to window size changes
** detect window size changes and exit the game with TILT
** how to determine if window size changes?
*** could check LINES and COLS on every ball move or clock tick?
*** or simply register a signal handler for SIGWINCH and
    set a flag to be handled in the main control flow

* when is reentrancy / atomic variable access a problem?
** some variable types are more susceptible to partial updates than others
** structs with multiple fields
** large numeric values (larger than the size of a register or a slot in mem)

* how signal blocking works and using it protect data
** both SIGIGN and blocking can prevent atomic operations from being interrupted
*** SIGIGN means "I don't care" ... drop the signal on the floor
*** blocking means "I sort of care" ... remember that the signal fired
** with blocking, it's important to keep the period of time the signal is
   blocked as short as possible
*** most of the time you'll have some method to make the main loop handle the
    condition from the signal

* review itimers and sigalrm
** there is only one itimer of each type that can be used
** if you want to drive multiple behaviors, use the shortest itimer setting
   required for any behavior and then just keep track of timer ticks
** x and y movement in bounce are two separate behaviors, each call to
   ball_move (the signal handler) updates the count
** adding another behavior means: add a counter for how many signal handler
   calls are needed before that behavior, and when you've counted that many
   do the thing
** bounce sets the itimer to trigger 50 times per second, so we just need to
   count to 50 to track one second

* paddle design
** dynamically calculate the width: COLS - 3 per side / 3
** width allows you to know where the left side and right side of the paddle are
** paddle_contact uses the paddle row, left, and right to determine if the
   ball is in contact with the paddle
** paddle_left and paddle_right need to limit movement
** never reference the paddle struct's data fields directly outside of paddle.c