Traditional Culture Encyclopedia - Photography and portraiture - If the photography of straight lines A and B in the plane is perpendicular to each other, then straight lines A and B are perpendicular. Is this a true proposition? Why?

If the photography of straight lines A and B in the plane is perpendicular to each other, then straight lines A and B are perpendicular. Is this a true proposition? Why?

Don't! Because it is assumed that A's photography is perpendicular to B's photography, it is easy to deduce that B's photography is perpendicular to (the plane formed by A and its photography). If b is perpendicular to a, then b should be perpendicular to the front plane, that is, b should be parallel to its photography, which is not stipulated in the original title! So it is not a true proposition!