Chaining Core Animation animations

Question

Which is the most elegant and modular way to chain animation in a Core Animation context?

I mean to do animations that starts just when other finis

Answer 1

I pull this off using the setCompletionBlock method to define a closure that triggers the next animation when the first one is finished:

[CATransaction begin]
layer1.property = new_property;
CATransaction.setCompletionBlock {
    [CATransaction begin]
    layer2.property2 = new_property2;
    [CATransaction commit];
}
[CATransaction commit];