The ornamental design for a flatrack, as shown and described.
FIG. 1 is a perspective view of the flat rack according to the present teachings;
FIG. 2 is a top plan view of the flat rack;
FIG. 3 is a bottom plan view of the flat rack;
FIG. 4 is a front elevation view of the flat rack;
FIG. 5 is a back elevation view of the flat rack;
FIG. 6 is a left side elevation view of the flat rack; and,
FIG. 7 is a right side elevation view of the flat rack.
Broken lines shown in the drawings illustrate portions of the flat rack, and form no part of the claimed design.
The jagged lines in the middle portion of the flat rack indicate that any portion of the article beyond what is shown forms no part of the claimed design.