What Robert Penner Never Told You About His 'Easing Equations'

In his epic work "Programming Macromedia Flash MX" Robert Penner introduced his easing equations to the world. Of course, the equations were standard curves used in interpolation throughout animation programming. However, these curves had never before been available in Flash. (Later, Macromedia would add them to the standard Flash libraries.)

Interestingly, it turns out that these curves with the names NSAnimationEaseInOut, NSAnimationEaseIn, NSAnimationEaseOut had existed on OS X/NeXTStep computers for nearly 15 years before Penner would bring them to Flash. Of course, the developers of Flash must have used NSAnimations before they brought the term 'easing' to the mainstream through the Flash UI. (Outside of Flash/COCOA the term 'easing' is never used in formal academic circles and is always refered to as interpolation.)

It infact appears that many ActionScript classes have Object-C/COCOA ancestors such as hitTest, NSURLRequest, NSURL, and many more.