Read the following papers and use them when working on your Design assignment.
S. Carpendale, “Considering Visual Variables as a Basis for Information Visualisation”.
OPTIONAL: W. S. Cleveland and R. McGill, “Graphical Perception: Theory, Experimentation, and Application to the Development of Graphical Methods”, Journal of the American Statistical Association, vol. 79, no. 387, pp. 531–554, 1984.