The ornamental design for keyboard practice aid, as shown and described.
FIG. 1 is a front perspective view of the keyboard practice aid showing the design, hand rests dotted;
FIG. 2 is a side view from the right thereof, the left being a mirror image thereof, hand rests dotted;
FIG. 3 is a front view thereof, hand rests dotted;
FIG. 4 is a rear view thereof, hand rests dotted;
FIG. 5 is a top view thereof, hand rests dotted;
FIG. 6 is a bottom end view thereof, hand rests dotted; and,
FIG. 7 is a perspective environmental view of design in an in-use position abutting piano keyboard, piano and hand rests dotted.
The broken lines shown herein are for illustrative purposes only and form no part of the claimed design. The environmental view illustrates the keyboard practice aid in use with a portion of a piano, which is disclaimed.
In FIGS. 1 and 3–7, the break line on the keyboard practice aid indicates an indeterminate length and forms no part of the claimed design.