@JeremyECrawford most wall spells describe either 10 foot panels (force, stone) or that you can shape it anyway you want as long as it stays on the ground (wind). Wall of fire just states the wall or ring shape. Can you shape the wall like an L for instance?
— Tomaz Saavedra (@tomsaavedra) August 19, 2020
The Wall of Fire spell in D&D can form a wall that is a straight line or a ring.
— Jeremy Crawford (@JeremyECrawford) August 20, 2020