Molecular machines rely on the directional motion of sub-molecular units, which is often achieved by built-in structural chiralities. In a recent scanning tunneling microscopy study, Jens Kügel and Markus Leisegang discovered that even achiral H2Pc and HPc molecules can perform chiral intra-molecular motion. The deposition onto a Ag(100) surface leads to an adsorption-geometry-induced chirality which is caused by a rotation of the molecules with respect to the high-symmetry directions of the substrate. As a result, tautomerization processes referentially occur in a clockwise or counterclockwise direction. In contrast to built-in structural chiralities that are fixed by the molecular structure, the direction of proton motion in HPc on Ag(100) can be inverted by a rotation of the molecule on the substrate. The result has been published in ACS Nano.