William Goldman 
Automorphisms of Two-Generator Free Groups and Spaces of Isometric Actions on the Hyperbolic Plane [PDF ebook] 

The automorphisms of a two-generator free group $/mathsf F_2$ acting on the space of orientation-preserving isometric actions of $/mathsf F_2$ on hyperbolic 3-space defines a dynamical system. Those actions which preserve a hyperbolic plane but not an orientation on that plane is an invariant subsystem, which reduces to an action of a group $/Gamma $ on $/mathbb R ^3$ by polynomial automorphisms preserving the cubic polynomial $ /kappa _/Phi (x, y, z) := -x^{2} -y^{2} + z^{2} + x y z -2 $ and an area form on the level surfaces $/kappa _{/Phi}^{-1}(k)$.