Watchkit animation implementations: clock face, animated charts, circular progress bar

I've seen some very basic demos of potential watchkit apps, and some appear to implement animations. Examples might be:

• A clock face with a moving second hand or even minute hand.


• A bar chart with bars that animate in, or who shape changes with new real-time data.


• A circular progress bar who's bar animates from zero to the current value.

The only way I've seen so far to do animations is by a sequence of images over a duration:

[imageView startAnimatingWithImagesInRange:NSMakeRange(0, 60) duration:1.0 repeatCount:0];

How would these previous animation examples generally be implemented? I can't imagine they are all done with image sequences. I don't think one can even layer images, and coordinating placement would be a nightmare.