To make a cut effect that would essentially “cut” out a piece of gui to “fill” a certain area, is a fairly easy thing to do.
You would need to use scrolling frames for this, so you would need to insert a scrolling frame into your gui and set its CanvasSize to {0, 0,} {0, 0}
And now simply parent the frames you want to “fill the area” and resize the scrollingframe to the area you want “filled”.