If scattering objects are irradiated diffraction pattern are produced, which are colorful and asthetic. These patterns appear learners very complex, because of many reasons. One of them is that they do not know sufficiently the relation between diffracting object and diffraction pattern, which is modelled by Fourier-Transformation. In this RCL experiment we offer about 150 diffracting objects, so the learner or user can study empirically the relation between diffracting object and diffraction pattern. On top they can study this relation on the basis of hypotheses or verify mathematical models. The number and diversity of diffracting objects as well as the visualisation of the transformation results by diffraction patterns (here optical Fourier-Transformation) render access to one of the most important transformations in physics and technical applications. The Fourier-Transformation is essential, important and elegant in modelling for the picture processing e. g. in radioastronomy, for the IR or optical spectroscopy, for the x-ray structure analysis in crystallography and for general signal processing in engineering sciences.