A command in the Pen menu of the Picture window, to set the colour of subsequent drawings.

You can specify the colour as one of the colour names in the Pen menu, or as a grey number betwene 0.0 (black) and 1.0 (white), or as a RGB sequence.

In an RGB sequence you specify a red value between 0.0 (no red) and 1.0 (brightest red), a green value between 0.0 (no green) and 1.0 (brightest green), and a blue value between 0.0 (no blue) and 1.0 (brightest blue). For instance, {0,1,0} is green, {1,1,1} is white, or { 1, 0.5, 0.5 } is pink.