Auto-cad Secret's Exposed.....!!!
Here is the third one from starting:-
3.)Take the edge out of Trim and Extend:-
Using the system variable EDGEMODE can simplify your Trim and extend functionality. Did you know that you can TRIM and EXTEND to non-existent edges?
0 Uses the selected edge without an extensions.
1 Extend or Trims the selected object to an imaginary extension of the cutting or boundary edge.