The ornamental design for a wallclock, as shown and described.
FIG. 1 is a front elevational view of a wall clock showing my new design;
and,
FIG. 2 is a right side elevational view of my new design, the top, bottom,
and left side views being substantially similar thereto.
The rear of the claimed design is plain and unornamented; the broken-line
outline of a mechanism is environmental only and forms no part of the
claimed design.