The ornamental design for a pedal pianotoy, as shown and described.
FIG. 1 is a perspective view of a pedal piano toy showing my new design;
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 plan view thereof; and,
FIG. 7 is a bottom plan view thereof.
The broken lines depict portions of the pedal piano toy that form no part of the claimed design. The dash-dot line is a boundary line and forms no part of the claim.