Mirrors
Setup
On the mirror setup screen, hit "Add Mirror" to create a new mirror. Use one finger to drag the mirror around, and use two fingers to rotate that mirror.
Up to 4 mirrors can be on the artboard at the same time.
Working with mirrors
Having a mirror on the screen mean everything you do to one side of it, will be reflected to the other side. Check out:
This can be used to do all tricks with symmetry.
note
As this feature is experimental, it may fail sometimes. Although I found it pretty solid during tests with horizontal and vertical mirrors, it's still a little buggy with mirrors on diagonals.