In recent years it has become clear that the scattering matrix of massless particles is a very special object. Massless particles are the backbone of our best theory of nature; the Standard Model of particle physics and gravity. In 2003, Witten succeeded in combining twistor theory and string theory to produce a new formulation for the scattering matrix of gauge bosons - massless particles of helicity plus or minus one. Since then finding a similar formulation for gravitons - particles with helicity plus or minus two - has been a very important open problem. In 2012, in collaboration with Y. Geyer (a PSI student), I found one such formulation. Not long after this first formulation was found, I found a second one with D. Skinner (a PI's PDF). Witten's discovery led to great advanced in our understanding of quantum field theory. It is not unreasonable to expect that the new formulations for gravitons might lead to similar advances in gravity.