In Part One we learned the basics of how a circle in basic one point perspective becomes an ellipse.
So how would another circle of the same size, say to the left of this one appear? Like this?:
In fact, in a perspective drawing like this, all ellipses on the ground plane will be oriented the same way - with their minor axes precisely vertical:
Interestingly, the same thing happens in two point perspective - as long as the sides of the (imaginary) cylinders are parallel, all the ellipses will be oriented the same way, in this case, vertically:
In Part Two we'll see how to apply this to a real drawing.