  Both 3- and 4-point scattering amplitudes for spin-1 massless particles
(gluons) and spin-2 massless particles (gravitons) are reviewed through
self-contained step-by-step derivation. Gluon and graviton interactions are
computed from on-shell diagrams by starting from complex momenta and
introducing spinor-helicity formalism. By Fourier transforming spinor variables
in momentum space, binarity is revealed in pure Yang-Mills scattering
amplitudes while absent to a certain extent for gravity indicating fundamental
differences in the probability spaces spanned by the two interactions.
