How to Test your Laser Line Level 

Super useful! Great help in cross-checking the true value of the current crop of cheap laser levels.

very nice and simple instructions, thanks

Thank you bro

A short and helpful video. Very nicely produced. Thank you!

Thank you! So simple, so genius!

Helpful video thanks you

Excellent, thank you my good sir. :)

Really good, thnx!

Awesome

The way you're checking both the front and side plains in the level test, you're taking the deviation between the marks on the wall from the original laser position, and the laser position after relocating the laser, and dividing by the distance between the marks. But I don't think you're making it clear that for the side plain, this distance is between the marks on the same wall, and for the front plain, this distance is between marks on opposing walls. Or am I misunderstanding what you're doing?