I'm actually using the routine right now in a puzzle game I'm developing that can be used on both color and grayscale calcs. It stores a special list based on the calculator type that contains the dimensions of the home screen and the color argument, which is either {8,16,1} or {10,26,12}. The screen dimensions are used for centering things in the opening menus and displays and such, whereas the color argument is thrown on to all the lines drawn (i.e. Line(X1,Y1,X2,Y2,C) ). It draws a normal line on grayscale calcs because of the fact that 1 is default, and a black (Color ID 12) line on color calcs. There is a slight dilation of object size/shape between grayscale and color graphs, but not a whole lot (at least from what I've observed so far) because even though the resolutions are different, the coordinates used are the same and the aspect ratios (1.616 vs 1.508) are very similar.