It's a faulty lens Karl, cant be the beam itself as they can only travel = in straight lines, or be reflected/deflected/bounced off solid or = mirrored (see below) angles. It would therefore seem your lens needs = spectacles, as it hasn't been 'milled' properly, but, somehow managed to = pass the quality control folks @ the manufacturers.
One other possible cause is, is it metallic paint or a very glossy = wallpaper (possibly highly shiny vinyl) you're bouncing the line on to? = if so, the metallic elemenets in the paint, or the sheen in the paper, = may be causing the 'bounce/reflection' you've mentioned? However, I've = never seen it @ any more than 5cm over a 4m run before, quite minor in = detail normally and usually detected as more of a 'smudge' than an arc.
I presume you've checked your findings using a 'square' edge, to ensure = it's not a 'trick of the eye caused by environmental factors, or very = very unsquare wall ?
New lens from retailer/manufacturer? Take it back?=20
John
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