Tetrisgender is essentially where you build up your gender identity over time, but once you feel like you've completed your gender identity, it disappears. Just like in Tetris, where you build up blocks over time only to have the lines disappear.
Tetrisgender individuals may use the pronouns block (he/she), blockim/blocker (him/her), and blockself (himself/herself). However, they can use any pronoun they feel like using that best represents the gender they are currently building up. The use of block/blocker/blockim/blockself is used when the individual more identifies as Tetrisgender as a whole than any other gender. Some Tetrisgender individuals will use different pronouns across their cycles, changin after their "lines" are cleared i.e. the gender goes away. To avoid having to correct pronouns every time the cycle changes, they will use Tetrisgender pronouns. The block- prefix is to be a definitive indicator that the person is Tetrisgender and may flip and flop their gender expression at any time.
The flag also represents the multiple pieces that make up a Tetrisgender person's identity, that fit together (until they are cleared away, of course.) It is possible for a Tetrisgender individual to build up multiple identities at once, all distinct from one another, but for them to be Tetrisgender, once an identity feels complete, it must disappear. The flag is misleading to some degree, as the lines are complete but not cleared, but the lines are kept uncleared, as if you added blank spaces in the flag to prevent the lines from being cleared, it'd seem like the person has "holes" in their gender expression. So the lines are kept uncleared to avoid that.
It is possible that, like Tetris "garbage lines", a Tetrisgender individual may build up an identity, but are building up multiple identities on top of that identity, only to block off the first identity from being completed. So one gender will always feel incomplete until the "top" genders are completed to disappear, giving access to the "bottom" genders.
One can be Tetrismale, in the sense that the identity you are building up is male, or Tetrisfemale, or Tetrisnonbinary similarly.
Occasionally a Tetrisgender individual will "clear" all of their gender expressions, similar to a "perfect clear" in Tetris, and they become Agender for the time being, until new pieces fall from above to stack up a new gender.
Some people will stack up multiple genders and clear multiple genders at once. Others sometimes will only complete one or two genders and clear them at once.
You can use the prefix Tetris- to refer to any gender you are building or stacking up that you feel will disappear once you feel your identity is completed.
Sometimes for some but not all Tetrisgender individuals, the whole goal of their gender expression is to build up and clear a gender. Other Tetrisgender individuals try not to clear their genders, and keep stacking them, but eventually are forced to clear some genders to prevent themselves from getting overwhelmed with too many gender expressions and identities. For ALL Tetrisgender individuals, whether they are doing so voluntarily or involuntarily, their gender expression builds up to the point it is completed, only for it to be cleared away. If the identity does not clear away once completed, they are technically not Tetrisgender.
Additionally, Tetrisgender can be applied to people who identify as tetriminoes, i.e. block-kin, or blockin. These individuals believe they are meant to fit in, but as soon as they do, they'll disappear, on top of the fact their gender identities clear when completed. They also physically wish to be a tetrimino. People who identify as an I-Tetrimino generally see themselves as desirable and liked, since I-Tetriminoes are generally the most desirable piece in a round of Tetris. These people are known as I-Type Tetrisgender, or I-Tetrisgender. People who identify as T-Tetriminoes generally don't realize their potential (or sometimes they do) and don't realize how much power they actually have, just like how so many people blow over a T-Tetrimino not realizing what a T-Spin is or how powerful that move can actually be. These people are T-Type Tetrisgender, or T-Tetrisgender. People who identify as S or Z-Tetriminoes see themselves as the least desirable and probably have an inferiority complex, because the S and Z-Tetriminoes are often seen as the least desirable piece in a round of Tetris. These people are SZ-Type Tetrisgender, or SZ-Tetrisgender. People who identify as L or J-Tetriminoes generally have a balanced view of their self-esteem because generally L and J-Tetriminoes are neither the most or least desirable piece in a round of Tetris. These people are LJ-Type Tetrisgender, or LJ-Tetrisgender. Blockin not only possess these characteristics, but really, truly believe they are a tetrimino on every level but physical. However, any Tetrisgender individuals can identify as a certain tetrimino based on how they view themselves in relation to others or how desirable they view themselves without being blockin. But blockin are generally Tetrisgender. Blockin might change which tetrimino they currently feel most aligned with according to their fluctuations in self-esteem.
Tetrisgender is directly related to being blockin, so further clarification is given on blockin, as there is currently no article out there describing blockin as blockin are extremely rare.
Occasionally blockin will dress up as a tetrimino to better feel connected to their blockself. They understand that it is physically impossible for themselves to be transformed into a tetrimino (until technology becomes sufficiently advanced to upload our consciousness onto a computer, to merge themselves with Tetris code) so for the time being, they cosplay their block identity in order to make them feel better about their image. They feel most at ease when doing so.