The polar model of gender as a means of describing our sex organs is fucking bullshit. That's a problem, though, because we're social creatures and we crave pattern recognition. Getting to say: "Yeah, I'm like THAT," feels awesome. Most of us want to experience gender euphoria, even if it comes at the risk of gender dysphoria and gender discrimination.
Allow me to propose an alternative.
In the books of Greenhouse, our protagonists are haoma, an engineered species that are very much like humans, except for a few key differences, including the fact that when they are adult-born (think: tank-grown clones), their sexual organs are, for a time, entirely mutable. A newly-emerged haoma in a resting state has no discernible sex organs at all.
A newly-emerged haoma in an aroused state may have breasts, or a penis, or a vulva, or any combination of the three. They only settle into a single permanent configuration after a transition called anthesis. With no established hierarchy of gender, haoma are free to self-express in whatever manner they wish. However, as a social and sexual species, it is useful for them both personally and as a community to have an agreed-upon shorthand for: "What you got under there?"
Enter Figures.
To signify the Figures, I borrowed the Chinese set of eight trigrams. Why? Well, they're in unicode, for one thing, so that helps. Also, they just fit. Three lines, broken or unbroken. Breasts, penis, vulva, top to bottom, absent or present. It's as simple as that.
I should note here that this is obviously a sort of cultural appropriation, but with all respect to modern and historical use of the bagua, given the countless number of meanings that the trigrams have held across their millennia of recorded use, I think they can probably contain one more. The patriarchy appropriated our bodies. Let us have these nice little lines, please?
Also, if you're asking: "What about my mouth and my butt?" The thing is, we're all just big tubes and the haoma are no different. Everybody has a mouth. Everybody has an asshole. (And anyone who insists otherwise is an asshole.) We don't need to add them to your Figure. It describes physical characteristics, not physical preferences.
So, let's run through their names and their trigrams.
Heaven Figure looks like ☰.
You have breasts, a penis, and a vulva.
Lake figure looks like ☱.
You have a penis and a vulva, but no breasts.
Fire Figure looks like ☲.
You have breasts and a vulva, but no penis.
Thunder Figure looks like ☳.
You have a vulva, but no breasts or penis.
Wind Figure looks like ☴.
You have breasts and a penis, but no vulva.
Water Figure looks like ☵.
You have a penis, but no breasts or vulva.
Mountain Figure looks like ☶.
You have breasts, but no penis or vulva.
Earth Figure looks like ☷.
You have no breasts, penis, or vulva.
I say "Looks like," because that's exactly how they work. You don't really have to think about them and you certainly don't have to remember their proper names. With a teensy bit of imagination, you just line up the figure with the body and it all falls into place.
If you have breasts and a vulva and no penis, you're not "a woman" under this model, you are/have Fire Figure and your trigram is ☲. If you have a penis but no breasts or vulva, you're not "a man" under this model, you are/have Water Figure and your trigram is ☵. Isn't that nice?
Every possible configuration is represented—and none of them MEAN anything, except signifying exactly what they describe. If you're a trans woman who's on hormones without surgery, you might be/have Wind Figure (☴) and that's great. You're not doing "woman" wrong. You just are as you are.
That's Figures. It's a system that does what it needs to and then gets out of the way. It was conceived for haoma, but it works equally well for humans. Maybe give it a try.