do `create some coordinates for line a xa1#=rnd(500) ya1#=rnd(500) xa2#=rnd(500) ya2#=rnd(500) `draw line a line xa1#,ya1#,xa2#,ya2# `create some coordinates for line b xb1#=rnd(500) yb1#=rnd(500) xb2#=rnd(500) yb2#=rnd(500) `draw line b line xb1#,yb1#,xb2#,yb2# `find gradient of line a ma#=(ya2#-ya1#)/(xa2#-xa1#) `find gradient of line b mb#=(yb2#-yb1#)/(xb2#-xb1#) `find x coordinate of intersection between lines a and b xi#=(yb1#-mb#*xb1#-ya1#+ma#*xa1#)/(ma#-mb#) `find y coordinate of intersection between lines a and b yi#=ma#*xi#+ya1#-ma#*xa1# `draw circle at point of intersection circle xi#,yi#,10 text 0,0,"Press space" wait key cls loop