“…Given a 4-orbit toroidal map, the minimal regular cover and the minimal rotary cover may or may not coincide; this depends on γ. For example, the minimal regular and minimal rotary covers of the map {4, 4} (2,1), (7,0) coincide. On the other hand, the covers of {4, 4} (4,3),(5,0) = {4, 4} (4,3),(−1,3) are distinct (see Figure 2 (a)).…”