I think an observation made in the now-dormant thread on patents has some bearing here.
There is no differential between hammock body and fly here. The guylines are pulling apart the sides of the body to keep it taut.The tent is suspended by the ridge from a heavy rope supported on trees or posts. It is kept taut on the side by tent ropes attached to stakes driven in the ground.
These guylines are not placed asymmetrically however. A modern hammock sold with symmetrically placed guylines on its body ought to be outside the domain of a patent that specifically claims asymmetric placement as a protected invention. In an earlier posting I pointed the Hennessey patent on tie-outs
hat-tip to ac33 for finding the 1904 book!
See also the image of the S3 "with fly" attached
It has, on close inspection a line visible which I don't think is a
fly's guyline. It's the dark one at about 7 o'clock from the tent body.
The guyline for the fly corner closest to the observer is barely visible.
Text describing the shelter describes the fly as having 6 guylines, so the
one at 7 o'clock is something else. Text description on Weather Resistence says
"The sides of the fly, as well as the hammock can be staked down to provide additional stability".