* function to check if point collinear or not
function cool_line ( x1 , y1 , x2 , y2 , x3 , y3 ) { if ( ( y3 - y2 ) * ( x2 - x1 ) == ( y2 - y1 ) * ( x3 - x2 ) ) document . write ( " " ) ; else document . write ( " " ) ; }