In this paper I briefly discuss and compare four easy derivations of the Lorentz transformations.
Two of these derivations assume the invariance of the Minkowski spacetime interval in inertial
frames and the other two assume the invariance of the d’Alembert operator in these frames. These
derivations are suitable for a first view of special relativity. Finally, I discuss the comment made
by Di Rocco on my original paper, ‘Lorentz transformations and the wave equation’ (2016 Eur. J.
Phys. 37 [http://dx.doi.org/10.1088/0143-0807/37/2/025603] 025603 ).