K40 Chinese Laser Air Assist and Triple Laser Line

This is a remix of "thing:1063067".

Now with option for 3 Laser-Line Modules (12mm).

Two laser-lines building a "X" to target the cutting laser-point.

The additional third laser line is there to easyly adjust the laser focus (by the distance to the target object).

To adjust the lasers, determined to try the ideal focus distance by testing. Is the focus determined, set the laser in such a way that the two opposing laser will form a congruent line. The third laser is to adjust in a way