We describe a class of non-linear transformations acting on many varia
bles. These transformations have their origin in the theory of quantum
integrability: they appear in the description of the symmetries of th
e Yang-Baxter equations and their higher dimensional generalizations.
They are generated by involutions and act as birational mappings on va
rious projective spaces. We present numerous figures, showing successi
ve iterations of these mappings. The existence of algebraic invariants
explains the aspect of these figures. We also study deformations of o
ur transformations.