Our understanding of scattering amplitudes is in perpetual refinement where new results lead to new insights, which in turn enable even more ambitious calculations. I will report on a recent observation that certain amplitudes and form factors are mapped to each other under the antipode of the Hopf algebra of multiple polylogarithms. I will discuss the two known instances of this duality which lead to constraining relations between four- and three-particle form factors and six-particle
