Can I use autolayout to provide different constraints for landscape and portrait orientations?

Is it possible to change the constraints when the device is rotated? How might this be achieved?

A simple example might be two images which, in portrait, are stacked one above the other, but in landscape are side-by-side.

If this is not possible, how else might I accomplish this layout?

I am constructing my views and constraints in code and not using interface builder.