First of all of course
you must choose the Brick.
It can be any shape or size:

being yourself 
in an unexpected place,
one where you’ve been
forbidden, is often brick enough
to break some Wall or window;

it may require
a bit more — the purchase
of a wedding cake,
a clothing choice no one foresaw,
stubborn insistence on a name or pronoun —
to crack a thicker wall or head
grown old and bitter
from long authority.

Next, the throw.
It should be overhand —
let it take flight, let it soar
over the ruins between you
and the target. Those
who fell before this time
will look up in the dark
and see a brighter sky and think
of a bird that can fly and land
wherever it wants;
they will rest easier.

You will not be alone in the fight.
Bricks that arc together land harder;
there are so many walls and windows to smash 
before they fully open the gates.

As for yourself in the aftermath?

You may retreat to save yourself
from what they do in response
but the ground where you stood remains yours;
though some may see it as a paradox,
you are also the brick you tossed,
a piece of something new yet to be built.