The elementary concept of conformal mappings, briefly reviewed in the Appendix, appears here merely as a motivation of a very routine change of variables (16) in an exactly solvable ordinary differential Schroedinger equation. This concept does not seem to be too much related to the subject of the paper itself, offering an exercise-like description of several well known facts about transition from a Casimir of su(1,1) and from its differential-operator representation to a solvable bound-state problem in Quantum Mechanics. MR2485574 Yahiaoui, S.-A.; Bentaiba, M. A group-theoretical method for Natanzon potentials in position-dependent mass background by means of conformal mappings. Internat. J. Theoret. Phys. 48 (2009), no. 2, 315--322. 81Qxx (33C90)