this is an example of a event handling
a event handle is when we handle events like a press of a key or a sprite movment
To unfreeze the mac book pro, there are two ways :
a. <span>Click the apple logo which is at the top
left of the menu bar and then select 'force quit'.
b. Hold down the option,
command, and escape buttons and then select 'force quit'. </span>
If all else fails, best option is to hold down the power button on the keyboard till it shuts down.