A model is presented, consisting of a single structureless particle on the
line subject to a potential with three minima, with an exactly soluble ground
level. In this model the ground level probability density becomes more
sensitive to the global shape of the potential as the distance between the
minima increases, so that for big enough distances small variations in the
potential bring a qualitative change in the probability density, taking it from
a unimodal, localized, distribution, to a bimodal one. We conjecture that this
effect, of which we have not found any precedent in the literature, may be
relevant in the design and characterization of mesoscopic devices such as
triple quantum well systems.