It remains possible to find new and simple physical explanations on Dna'S basic geometry and "mechanics". For example, how Dna'S rotation in different situations changes, or perhaps remains unchanged, under the influences of external forces. Specifically, this has implications for the understanding of the structure of nucleosomers. The tools are fun mathematics and physics, whose understanding does not require special prerequisites, and in this context, the "secrets" of rope slaughter will be discussed. Geometric and topological constraints such as White Teoremet will be compared with the latest results from the research at DTU.