Rule 63 is the only of those weird 'internet rules' I know about having mainly safe outcomes (if the origin is safe too, of course). Basically, it says any character with a recognizable sex/gender has the symmetrical version. A way to play on these kind of stereotypes, in other words. Because while I can call Yamato 2199 the bestest remake ever (mistake intentional) I also made a lot of frowning at the fanservicey scenes. [I'm not against fanservice per se, but I'm for a modicum dose and a bit of balancing.]
Apologies for the not-so high quality of the linework and anatomies: after depression and after the shaky hands came back in full force I'm basically retraining myself to draw.