A four dimensional integrable system is semitoric if one of the componentsof the momentum map is proper and generates a circle action. In the casewhen each fiber of the momentum map of the circle action contains at mostone singular point of focus-focus type, called simple, semitoric systemswere classified by Pelayo & Vu Ngoc about 10 years ago. We will discuss theclassification when the simplicity assumption is not satisfied. We found abijection between semitoric systems up to fiber-preservingsymplectomorphisms and marked Delzant VPIA polytopes in the VPIA plane up toautomorphisms of the VPIA plane, constructed form the momentum map image.This talk is based on joint work with J. Palmer and A. Pelayo; seearXiv:1909.03501.