Interpenetrating Surfaces e peer through several interpenetrating approximately ellipically shaped surfaces. Electrons in molecules normally move a lot faster than the nuclei. This leads to the concept of effective potential energy surfaces that govern the motion of nuclei. These surfaces interpenetrate, and intersect in various ways. Their intersection actually causes a breakdown in the assumption that the motion of the nuclei can take place on the surfaces in the first place. The breakdown leads to interesting experimental consequences. Here we peer through several interpenetrating approximately ellipically shaped surfaces, transparent enough to see through into the next surface. Caustics develop as the viewing direction goes parallel to the surfaces. The breakdown of the so-called adiabatic" approximation is suggested by the broken nature and color chaos of the surfacesInterpenetrating Surfaces We peer through several interpenetrating approximately ellipically shaped surfaces. Electrons in molecules normally move a lot faster than the nuclei. This leads to the concept of effective potential energy surfaces that govern the motion of nuclei. These surfaces interpenetrate, and intersect in various ways. Their intersection actually causes a breakdown in the assumption that the motion of the nuclei can take place on the surfaces in the first place. The breakdown leads to interesting experimental consequences. Here we peer through several interpenetrating approximately ellipically shaped surfaces, transparent enough to see through into the next surface. Caustics develop as the viewing direction goes parallel to the surfaces. The breakdown of the so-called "adiabatic" approximation is suggested by the broken nature and color chaos of the surfaces