To turn the example above into a patterned line draw, simply set a drawing
pattern, such as:

    SetDrPt(&rastPort, 0xAAAA);

Now all lines drawn appear as dotted lines (0xAAAA = 1010101010101010 in
binary).  To resume drawing solid lines, execute the statement:

    SetDrPt(&rastPort, ~0);

Because ~0 is defined as all bits on (11...11) in binary.