Who needs a 1920×1080 OLED display when you can have an 8×8 matrix of LED goodness ... be perfect for a common cathode matrix. Of course [Kathy] only had a common anode matrix, so 8 PNP ...

Each LED anode is tied together on each horizontal layer. Each cathode is tied together on each vertical column. This allows the TinyDuino to control any one LED by knowing which of the 9 columns ...