Definition of "box-like"

Once inside it widens, but only to make room for a big box-like building with the worn and greasy look of the slum tenement that is stamped alike on the houses and their tenants down here, […]

1890, Jacob A[ugust] Riis, “The Down Town Back-alleys”, in How the Other Half Lives: Studies among the Tenements of New York, New York, N.Y.: Charles Scribner’s Sons, page 31

The majority of locomotive bodies have vertical sides, partly to simplify construction and partly to make the utmost use of the permissible loading gauge. This tends to produce a box-like appearance, which is uninteresting in itself but can be improved [...].

1961 May, B. A. Haresnape, “Design on the railway: Part Three”, in Trains Illustrated, page 302