I've tried to make a parametric wall

[Joseph_Oster]

Your loft surface is horizontal (a floor), not vertical (a wall). Use Z vector instead of Y:

Parametric wall_2022Oct26a.gh (14.8 KB)

Many examples on the forum, did you see these from seven years ago?

Brick Wall, Bricks intersection

Simple brick joint pattern

And something more recent (3 years ago):

Control gap between bricks in a wall grasshopper

You didn’t post a model so I can’t speak to your particulars. I took a copy of the model referred to above and added a cyan group that offers a “Gradient” option affecting the gap. The output of the Range component can be reversed so the gap diminishes toward the top instead of the bottom. I replaced a pair of Split Tree components with a better way to cull bricks on alternate rows. There are some assumptions made here that I’d rather not get into changing, though I can see reasons to do so.…