  A new version of an elementary PT-symmetric square well quantum model is
proposed in which a certain Hermiticity-violating end-point interaction leaves
the spectrum real in a large domain of couplings $\lambda\in (-1,1)$. Within
this interval we employ the usual coupling-independent operator P of parity and
construct, in a systematic Runge-Kutta discrete approximation, a
coupling-dependent operator of charge C which enables us to classify our
P-asymmetric model as CPT-symmetric or, equivalently, hiddenly Hermitian alias
cryptohermitian.
