All you have to do is compare a vertical (portrait) version to a horizontal (landscape) version . Choose any subject you want.
I took these photos a couple of months ago. I drove up to the Dallas Travel Show and stopped on the way home to see some of the Bluebonnet Trail. I really wish the weather was better. Would have been fantastic if the sun was shining rather than the dreary rainy day it was. But the flowers were still blooming and made up for the weather.