Different-color plots on one set of axes

I need to draw multiple lines of different colors in one 2D plot.
Looking for clues as to how to do this, I found Test67 in the "examples" 
subdirectory. It shows red and blue sine waves each in its own cube.
It appears from that example that color is a property of the Display 
object. But experimentation with two data vectors representing two 
different lines showed me that they must be associated with only 
one Display object to have them appear on one set of axes. What to 
do?