Which laser beam is not visible?

Question

lasers

I would like to put an inscription on the wall of the building, but so that it is impossible to see where the beam is shining from. Is that possible? In the direction of which lasers to look when buying?
Also interested in:
1. Is it possible to shine through the glass of a window?
2. The distance is about 50 meters
3. What to make a nozzle for the inscription?

Answer 1

1) So after all, no one will see the inscription then! And if the inscription is visible, then from the side of the wall, in any case, you can see where it shines from.
2) a laser is a dangerous thing, powerful lasers (namely, such are needed to display a large inscription) can easily blind a person
3) well, an infrared CO2 laser will be the most inexpensive and powerful "invisible option"