confidence.interval
If confidence.interval=FALSE (default), the 95% confidence bands are not plotted. If confidence.interval=TRUE, the 95% confidence bands are plotted as shadows.
line.color
colors for the lines. Default are "black", "grey30", "grey50", "grey60", "grey70", and "grey80" for A1B2 vs. A1B1, A2B1 vs. A1B1, A2B2 vs. A1B1, A2B1 vs. A1B2, A2B2 vs. A1B2, and A2B2 vs. A2B1 respectively.
legend.position
the position of legend: "left", "right" (default), "bottom", "top", or two-element numeric vector (e.g. c(0.6,0.9))