The ornamental design for a chair for tricycle, as shown and described.
FIG. 1 is a perspective view of the back, top, and left side of a chair for tricycle showing my new design;
FIG. 2 is a top view thereof;
FIG. 3 is a bottom view thereof;
FIG. 4 is a front view thereof;
FIG. 5 is a back view thereof;
FIG. 6 is a right side view thereof;
FIG. 7 is a left side view thereof; and,
FIG. 8 is a left side view of the chair for tricycle in an environment of use with an unclaimed tricycle.
The broken lines throughout the drawing figures depict unclaimed portions of the chair for tricycle and an unclaimed tricycle. The broken lines form no part of the claimed invention.