Void as mass

Rachel Whiteread's work is basically presenting spaces as mass, and sometimes she creates wonderful objects. I liked "House" (above) where she poured concrete in the rooms and tore the house down. It gives architect students a way to see at least one dimension they are dealing with.
Her new piece in the Tate takes the ticket for me, though, as it gives a sense of the lightness and thinness of what's missing. It's piles of the interior space of cardboard boxes, stacked high.