I had trouble, thinking of a suitable building I could visit and as we are in lockdown due to covid-19 I opted to draw a stack of books as the exercise suggested.
I set up a stack of books and a small chocolate box, I offset a box on top of this. My viewpoint was close to the subject and elevated above, this seemed to skew the squareness of the box.
The vanishing points was indeed quite far off the paper, I do know of a technique to overcome this issue, although I didn’t use it in this example. I felt the exercise went fairly well, a building would have been required a lot more accuracy, and offered more of a challenge, the books can have curved lines and wont look off, where as a buildings structure needs to appear sound or it will look out of place.
I have seen some really nice drawings of buildings that have hand drawn lines, that aren’t straight, the understanding of perspective does seem to be key, even if you mean to distort or exaggerate angles in the final work, I will look to see if I can add some looser hand drawn line work in any upcoming drawings of buildings.