# Set line styles suitable for projector
    set style line 1 \
        linetype 1 linewidth 4 \
        pointtype 31 pointsize 4 
    set style line 2 \
        linetype 2 linewidth 4 \
        pointtype 20 pointsize 4 
    set style line 3 \
        linetype 3 linewidth 4 \
        pointtype 13 pointsize 4 
    set style increment user