PPT Slide
if (line (pi, pi-1) has points below it)
try forming lines with previous points;
take the line that doesn’t have any points left below it; }
if (prev. intersection pts exist above intersection of li, li-1)
try intersection pts of prev lines;
take the point that doesn’t have any lines above it; }
draw intersection pt of li and li-1
Using left/right -- > above/below properties