Question: can you explain to me what parallax is

Nazim Bharmal answered on 14 Mar 2012:

Parallax is how parallel two lines are together (!)

Imagine you take two lines, like the rails that trains travel along, then at the start they are some distance apart. If you go along one of them and then measure how far away the other one is, if it is the same distance then the two lines (or rails) are parallel. They will never touch each other but they will also never go apart.