I haven't found one thing on BGG forums, and I found it ambiguous in the rules. Maybe it's just due to my poor english... Back to the point:
"Rotation. The player rotates an area tile by 90 degrees (in either direction) or by 180 degrees, thus moving the wall to either block or open up a Detective's line of sight"
I can interpret it in three different ways:
a) player can rotate a tile by 90 or 180 with no restrictions and it may change the Detective's line of sight (that's the way people around me play)
b) player can rotate by 90 degrees freely, but for 180 degrees ONLY IF it changes the Detective's line of sight
c) player can rotate - by 90 or 180 degrees - ONLY IF it changes the Detective's line of sight (that's the option I would choose)
(It sounds like a detail but it can sometimes change the game - you can't prepare tile with proper rotation for later in the turn if it doesn't change the line of sight right now...)
How do you play?