The billboards along the freeway as I drove home from the supermarket had long since abandoned the kind of direct, frontal approach of days gone by.

For example, rather than touting head-on the physical or literal characteristics of a particular brand of cigarette, the contemporary version provided lusciously appealing photographs of cowboy life, with the name of the manufacturer not only subordinated, but actually truncated down to where only a portion of the letters were visible.  

Even the familiar, literalistic rectangular shape of the billboard had been effectively obliterated by additional pieces cleverly attached to the traditional outer boundaries, enabling the imagery to float more or less freely in "mindspace."

This was no longer something to be rationally and sequentially processed as (a) a billboard, (b) a billboard touting Marlboro cigarettes. It was more a window into another dimension—and one that was actually quite a bit more appealing than the drab concrete grayness of the freeway along which it was placed.

It had ceased to be primarily a structural entity in the physical landscape;   it had ascended to the role of imagic element in a collective "mindscape."