Example of a 1 point perspective from a student's sketchbook but not an example for the sketchbook assignment
Another example of a 2 point perspective drawing. This example presents many lines converging from the planes of the steps to 2 separate vanishing points. The two vanishing points run off the page and are cropped. In this complex drawing the horizon line is above the stair case. In the perspective assignment in some cases people will need to add additional sheets of paper to their assignment in order to depict the vanishing points (and of course the perspective assignment will be use photographs - not drawings to work from for the perspective assignment).
Bennie Peters