Issue 203: This artwork is based on a bifurcation diagram that emerged from our paper on the Estrogen paradox that was recently published in the Journal of Mathematical Biology. In this paper, we proposed a novel mathematical model that accounts for the interactions between cancer cells, the estrogen hormone and the p53 protein. The model's bifurcation analysis suggests that the estrogen paradox could be the result of an interplay between estrogen and p53. It further provides explicit conditions under which the paradoxical effect of long-term treatment may be prevented. Active-tumor cells are eliminated in the purple areas and persist in the red and green ones. To reflect the paradox our paper addresses, the bifurcation diagrams have been arranged around a Penrose triangle.