The ornamental design for a pi (π) character doll set, as shown.
FIG. 1 is a front view of the PI (π) character doll set of the present invention showing a doll design for a PI character doll and a detachable accessory, the doll and accessory forming a PI(π) character doll set of the present invention; (the π symbol on the chest of the doll design is flat indicia);
FIG. 2 is a rear view of the PI(π) character doll set of FIG. 1;
FIG. 3 is a front view of the PI (π) character doll set of the present invention of FIG. 1 with a cummerbund of the doll design lowered to expose flat indicia representing the numerical expansion of π as well as the π symbol on his chest;
FIG. 4 is a left side view of the PI (π) character doll set of FIG. 1;
FIG. 5 is a right side view of the PI (π) character doll set of FIG. 1;
FIG. 6 is a top view of the PI (π) character doll set of FIG. 1; (the small circles of the top view of the accessory are flat indicia);
FIG. 7 is a bottom view of the PI (π) character doll set of FIG. 1; (the mathematical equation for π, RADIUS, Diameter and circumference and related circular and straight line segments are flat indicia); and,
FIG. 8 is a perspective view of the PI(π) character doll set of FIG. 1.
The broken line showings are for the purpose of illustrating environmental structure and form no part of the claimed design.