The ornamental design for a triangularpouch, as shown and described.
FIG. 1 is a front perspective view of the triangular pouch shown in an open and unfolded position;
FIG. 2 is a front view thereof;
FIG. 3 is a rear view thereof;
FIG. 4 is a left side view thereof;
FIG. 5 is a right side view thereof;
FIG. 6 is a top side view thereof;
FIG. 7 is a bottom side view thereof;
FIG. 8 is a front perspective view of the triangular pouch, shown in a closed and folded position; and,
FIG. 9 is a rear perspective view of the triangular pouch, shown in a closed and folded position.
Broken lines representing stitching and the broken lines showing tabs on the top edge of the triangular pouch illustrate unclaimed portions of the design. The broken lines shown in FIGS. 8 and 9 depicting a scooter and a wheel represent environmental subject matter. The broken lines form no part of the claimed design.