In the realms of prehistoric S100 history, someone developed some colour & colour graphics extensions for the DG640/TCT-PCG.
By halving the horizontal pixel resolution, each pixel can be assigned 2 bits and these two bits used to select one of 4 colours (00, 01, 10, 11)
to which a nominated colour from a palette of 16 colours is assigned.
The screen shot shows a simple PCG editor for it.
The colours chosen are 00=GREY, 01=RED, 10=BLUE, 11=YELLOW.
The grid is the editing platform for 4 adjacent PCGs with the resultant PCG chars shown above it.
The WASZ keys are used to move the editor cursor round the grid with 1230 keys used to select the colour.
