The ornamental design for a desk top, as shown and described.
FIG. 1 is an isometric view of the desk top of the present invention as a whole.
FIG. 2 is a top view of the desk top of the present invention in plan.
FIG. 3 is a right side view of the desk top of the present invention; and,
FIG. 4 is a right side view of the right edge of the desk top of the present invention.
The desk top has a top with a parallelogram shape with one curved side. The desk top also includes front and back edges which are straight and have a profiled shape.