Basic Linear Perspective Diagrams

In one-point linear perspective the infamous "vanishing point" is not so much some intangible object in the distance as it is the location (and direction) of your eye in space. Close one eye and wherever you point your open eye, that's where vanishing point is located. Instead of "horizon line" I prefer the term "line of sight" as that also becomes tangible and not a remote abstract conception in the distance. In truth it is both infinitely far and near but I find that making this concept more personal helps students understand the process better. If you are interested check out the book "The Rediscovery of Linear Perspective" by Samuel Edgerton. 

Above are various illustrations that I have found/scanned/collected over the years related to one, two, and three-point linear perspective.