I shined my flashlight on a wall in terror. It was 2 in the morning at my place and I thought I heard a voice in my head. At first when I saw what was in my light, I jumped back because it looked monstrous. Then I realized that there was no true monster and I was probably hearing things such as the wind. But I did see 4 shapes.
The first shape seemed really natural and common.
The second shape seemed sort of like the first one, though some differences were there. We go in this shape more than you think.
The third one fit ironically three descriptions.
The fourth one is the third one stretched. I was estranged that there was only one curve, not two.
So I ask you, what is the relation between these four shapes? Maybe it will help to identify the shapes first.