Agreed, the kind of tent you show is a box tent, a post in each corner and maybe (if there big) one in the center or so to hold the center up. Even if pulling fully taught, you will see folds and signs of those posts in the corners, even more so when tight. But honestly you don't want it super tight, wind blows and theres no give, the tent can easily tare.
I tried to find a photo of the tent me and some friends used as a main living tent on a two week outing, it was similar to what you have to show an example, but couldn't find any clear shorts of it.