FIG. 1 is a front view showing a coupling of two adjacent front panels in a closed condition;
FIG. 2 is a back view thereof;
FIG. 3 is a side view thereof;
FIG. 4 is an opposite side view thereof;
FIG. 5 is a bottom view thereof;
FIG. 6 is a top view thereof;
FIG. 7 is a longitudinal section view thereof;
FIG. 8 is a transversal section view thereof;
FIG. 9 is a perspective view thereof;
FIG. 10 is a perspective view of the panels of FIG. 1 in a partially opened condition;
FIG. 11 is a front view of another embodiment showing a coupling of two adjacent front panels in a closed condition;
FIG. 12 is a back view thereof;
FIG. 13 is a side view thereof;
FIG. 14 is an opposite side view thereof;
FIG. 15 is a bottom view thereof;
FIG. 16 is a top views thereof;
FIG. 17 is a longitudinal section view thereof;
FIG. 18 is a transversal section view thereof;
FIG. 19 is a perspective view of the panels of FIG. 11; and,
FIG. 20 is a perspective view of the panels of FIG. 11 in a partially opened condition.