Tried one leg.... Beyond unstable. Need a rear shot to work out how they did it vertical, the ratchets can't take any weight

Edit....

Ok, spin upper leg 90 degrees to allow a couple of clicks past verticals, and weight pulls leg back to near vertical. But waist has no support, so is floppy side to side, and nothing to lock in the back of the legs, so these flop around in the breeze...