Make a line drawing of a building or several buildings seen corner-on.
I was planning to do this exercise in town but it is raining this morning. So I did it at home overlooking my neighbour across the road from my first floor window.
It is a pencil drawing in my A4 cartridge sketchbook. The drawing is quite small because I have to reserve room for establishing the vanishing points. The building is not ideal as it’s extension at the back is irregular but the original nearside of the building is OK.
First I established my eye level (horizon) then use the line along the eave of the roof and the brick line meeting the horizon to set the left side vanishing point and the brick line and the top of the front window to set the right side vanishing point.
I am quite happy with the drawing even though it is a bit too small. The nearside of the building looks believably solid and three dimensional but the back extension part is not so. I found establishing the vanishing points first is helpful.
The second part of this exercise is to check the accuracy of the drawing of Sir Muirhead Bone, Rome, 1910 (pencil) by copying a simplified version of it into the sketchbook then continuing the perspective lines to the vanishing point. I cheated a bit. I drew the perspective lines on the original drawing and established the vanishing point then drew the simplified version with the same measurements. I doubt I can do a copy even a very simplified version without the perspective line.
Note, I found all the perspective lines of the original met at the vanishing point except the one at the street level of the buildings.