If it came out on the PC first and Macs have it now and its now included standard where before it used to be an optional add-on, then its a PC innovation that raised the bar.
OTOH, if Apple added it to the base product line and then all the PC makers started including it as a standard feature then its an Apple innovation that changed computing for the PC world.
Under which scenario does your light pen fit? Oh right, its neither since light pens are not included standard on either PCs or Macs.