There's an architectural shift when you drive out of downtown on I-394. The buildings whether squat or soaring, have mass, solidity and a sense of permanence. They are built for stout and organized on a sensible grid. No one who begins buildings like those envisions a moment when they might come down.

As you thread your way towards the western suburbs, there's a not-so-subtle change in tack. You can't fault the buildings for brevity of height, so much as lack of conviction.

Star Tribune columnist, James Lileks described it much better than I last year when he wrote about the aging suburbs, where we can now have a kind of nostalgia for the defunct chain restaurants and big box stores as they change hands, sort of a, "Oh yeah, remember when that was a Bennigan's?" wistfulness.

This routine westward ho transition plagues every city, although it manifests at every compass point. It's not just the higgledy-piggledy city planning, but the feeling that it's all subject to a sell-by date.

I'm only an armchair architect, and nowhere close to an economics expert, so I offer no cures, merely an observation. It started as I was walking along the major business thoroughfare in Savannah (where I'm supposed to be hiding out another hideous winter, ha, the jokes on me), a city that ranks unusually high for urban layout.

But this doesn't matter, because the point of my interest can be seen in any city's older business district. Not carved in stone, but close, they are the terrazzo entryways, speckled and polished, sometimes inlaid with brass lines forming intricate designs or store names. The most beautiful ones have a touch of art deco about them. They speak of a time when either the economic clime was way better or at least hopeful. No pessimist puts in a floor like this.

Terrazzo is one of those old but new again mediums. Ancient terrazzo consisted of marble chips, waste from grander construction bound together with clay and goat milk for sealer. In later times it has been made with cement and aggregate of quartz, marble and such, then ground and buffed for a matte shine. And for that reason it's a recycled sustainable material.

Nowadays terrazzo will get you LEED credits.

As an armchair archeologist as well I also wonder how generations from now will see us at this point, will anything original from the past 30-40 years remain? Should it? Buildings seem to be regularly renovated because they got it wrong in the first place or never meant them to last, the results embarrassing enough to be torn down and replaced. Or do we need a certain passage of time before we appreciate, like the mid-century modern that's suddenly more popular. Is it possible we will actually yearn for examples from the 80's?

I'm talking buildings and should be talking simply signs, but that reflects the same short-lived life of the metal storefronts and tilt-up construction, festooned with canvas banners or the drive up and drop-off marquees. Surely someone will leave a comment setting me straight about high taxes and impossible government regulations, and I don't pretend to understand much of that beyond the surface. I know that businesses need to be able to move quickly with the market.

I should probably just wax lyrical about the strong graphic qualities, beautiful color combnations and silky sheen of these well-trafficked landings. But two of the four stores pictured are still going strong after a century, maybe those entries leave a little less option for failure.

I just wonder if there's a chance that businesses will ever build again with such commitment, such faith that they will prevail and withstand the cycles of boom and bust to pour a terrazzo floor with their name boldly blazing like these in my photos?