Is there a way to delete a shape with an extrusion I'm trying to delete a part of a shape with an extrusion.
The shape:





This is to make a fluid simulation where blocks of water will flow in each of the top three holes and out through the bottom three holes.
Use the inset tool (Keyboard shortcut: I)

Select the faces, inset, and use the inset individual option.

from there you can extrude.



To make a though cut, select faces on top and bottom, inset, delete the newly created faces, select the edges on top and bottom and use bridge edge loops to connect top and bottom. (bridge edge loops