As for (1), at first glance the silhouette resembles the shape of a thigh that is interrupted midway, but structurally it deserves to be called/considered a joint instead.
It's said that "she looks humanlike at a quick glance, but if you look closely she's chimeric", personally it became a favorite gradual appreciation factor.
Also, as a result of the addition of (1), I was able to eliminate the "constantly M-shaped spread-leg position" that is unique to spider girls, which could be seen as "vulgar". ((1) is normally closed just like the legs)Hair starts from here