I just wanted to try drawing an interior scene whilst standing up with a small sketchbook. I find standing with small sketchbooks uncomfortable. It’s hard to keep the sketchbook and my hand still, so straight lines suffer!
I didn’t look closely enough at the glasses on the table. They are at different angles in my drawing. Another thing: because the I am holding the book I don’t think to stand away from the picture and look for flaws. I didn’t notice lines that aren’t parallel, for example. I have to remember to hold the book away from me now and then, or even put it down and look from further away.