The ornamental design for a mat with embeddedsymbols, as shown and described.
FIG. 1 is a top plan view of a mat with embedded symbols showing my new design. The bottom plan view forms no part of the claimed design.
FIG. 2 is a front elevational view thereof, the rear elevational view being a mirror image;
FIG. 3 is a right side elevational view thereof, the left side elevational view being a mirror image; and,
FIG. 4 is a partial exploded view thereof showing an enlarged symbol from FIG. 1. The dash dot dash lines in the drawing form no part of the claimed design.