i tried using (run without screen refresh)

but it becomes so laggy that i cant run it ,i know i can just use pen size(I'm using it rn) but is there a way to properly draw a filled rectangle?

project here

Script can be shortened down to this:

How it works is that it draws the two given x coordinates at the given y level, and changes the y level every single tick which causes it to draw from side to side. This makes it so that you don't need to really worry about the x axis because the only thing that changes is the y axis.
One thing to note is that I used a join block instead of if statements to change filly because JS treats +n as a number.

kk ty