  Recently, some eccentricity-invariant properties of random, isotropic,
two-dimensional (2D) systems of conductive ellipses have been reported [Phys.
Rev. B \bf{104}, 184205 (2021)]. Moreover, the authors suggested that this
invariance might also be observed in systems with other particle geometries
having zero-width sticks as the limiting case. To check this suggestion, we
studied 2D random systems of isotropically-placed, overlapping, identical
discorectangles (stadia) with aspect ratios ranging from 1 (disks) to $\infty$
(zero-width sticks). We analyzed the effect of the aspect ratio and the number
density of conductive discorectangles on the behavior of the electrical
conductivity, the local conductivity exponent, and the current-carrying
backbone. Our own computer simulations demonstrate that some of the properties
of random, isotropic 2D systems of conductive discorectangles are insensitive
to the aspect ratios of the particles.
