Get the vertical axis of object's array

Hello,

I encourage you to go through the tutorials and experiment a little:
https://processing.org/

Try this:

translate(width/2, height/2);
rotateY(howMany);
translate(-4*16, -4*16, -4*16);  //This will translate it to center

Most importantly worth through this by commenting lines and seeing what each one does.

:)