I just saw a commercial for a device called “Laser Straight” (the commerical is also on their website). Toward the end of the commercial (after the bit saying why normal laser pointers are no good), they claim that Laser Straight can go around corners, and show it continuing around a corner, all the time staying on the wall.
Can anyone explain how this thing can work?
Well frfom what I can see on the website, all the red lines look computer-generated, and in any case it would be a straightforward trick to angle a wall inwards so any ordinary light will illuminate it, but make things seem that it goes outward and therefore ‘round the corner’
WAG:
Maybe you put it on an opposing wall, shining over to the corner in question?
Don’t you love the description on their website?
I don’t think “adheres” is a word that describes light very well. And if the laser were powerful enough to leave marks on your walls, that’d be the least of your worries.
I’m not trying to defend their claims (because I’m more than a little skeptical about the going around corners bit)… but I’m fairly certain they mean the DEVICE adheres to any surface, not the beam itself 
:smack: That makes a bit more sense.
As for how they do the “around the corner” trick, all you have to do is place the device on an opposing wall that has a view of both walls to be illuminated.
Hmm, I’m going to have to watch the commercial on TV again. I just noticed there’s some tiny text under the “Goes around corners” bullet (I rewatched to see exactly how they couch the claim, to see if the “shining on a corner to get both walls” argument agrees with what they’re saying–I’m not saying it isn’t the CORRECT answer, I’m just not sure that they imply it )
Looks similar if not the same as a unit I bought from Sears last fall. It uses a prism to spread the laser beam to create a line rather than a dot. The beam has a spread of perhaps 30 degrees. So,if the unit is stuck on a wall, the line will hit the corner and extend across the perpendicular wall for some distance.
The linked site doesn’t show much detail, but the unit I bought from Sears has a magnetic base. There’s an attachment that pins to the wall and the laser unit is held on by the magnet.
Thank you one and all. I’ve been wondering about that commercial, too. 