We claim the ornamental design for a positionable reflector, as shown and described:
FIG. 1 is a lower right front perspective view of my positionable reflector with unclaimed features shown in dashed lines;
FIG. 2 is a front elevational view of my positionable reflector with unclaimed features shown in dashed lines;
FIG. 3 is a right side elevational view of my positionable reflector with unclaimed features shown in dashed lines;
FIG. 4 is a top plan view of my positionable reflector with unclaimed features shown in dashed lines;
FIG. 5 is a rear elevational view of my positionable reflector;
FIG. 6 is a left side elevational view of my positionable reflector with unclaimed features shown in dashed lines;
FIG. 7 is a bottom plan view of my positionable reflector with unclaimed features shown in dashed lines;
FIG. 8 is a left front perspective view of my positionable reflector in one condition of use with unclaimed features shown in dashed lines; and,
FIG. 9 is an upper left front perspective view of my positionable reflector in another condition of use with unclaimed features shown in dashed lines.
The characteristic feature of the design resides in the capability of the positionable reflector to attain different shapes when in use installed on a light source.