The TLC chips in this sheld are driving all 16 LEDs all of the time. There’s no multiplexing, and the Arduino board only has to write new values to the Arduino when it wants the display changed. Scaling it up to a 8x8 matrix would be possible, but annoying. You can use two TLC5940’s to drive the 24 pins for the 8 columns, but they you’d need to reload the TLC for each row. That might refresh too slowly. You could use 4 TLCs and drive two rows at a time; that might be a better multiplexing solution.