  We present a holographic construction of solutions to the gravitational wave
equation starting from QFT scattering amplitudes. The construction amounts to a
change of basis from momentum to $(2,2)$ twistor space, together with a
recently introduced analytic continuation between $(2,2)$ and $(1,3)$
spacetimes. We test the transform for three and four-point amplitudes in a
classical limit, recovering both stationary and dynamical solutions in GR as
parametrized by their tower of multipole moments, including the Kerr black
hole. As a corollary, this provides a link between the Kerr-Schild classical
double copy and the QFT double copy.
