Although crime is on the down-swing in Cambridge, those who operate the cashiers alone in the wee hours remain vulnerable.

Two months ago Stephen Amoako, a native of West Africa who works the late-night shift at Christie's--another 24-hour convenience store, located on John F. Kennedy Street--was beaten and then robbed by two youths.

But most who work the late-night shift have adapted to the routine.

Shifts generally begin between 10 and 12 at night and finish between 7 and 8 the next morning.

In each store there is a very similar traffic pattern: Harvard students coming and going until 2 or 2:30 a.m., occasional homeless persons wandering in between 3 and 5 and the office crowd starting the new day at 5 a.m.

The graveyard workers develop various preferences for this schedule.

"People in the morning just want their newspaper and cigarettes," Burke said. "The Harvard students are annoying; they try to come in here with their credit cards and think it's a grocery store."

Others like Poller at Kinko's find the period from 3 to 5 best because there are fewer demands from customers.

Another fixture of commercial life after hours is the homeless.

A few store employees say the habits of some homeless--including chugging 21-percent alcohol Listerine and dozing off on top of copy machines--often prove entertaining. Most early-morning cashiers leave them alone.

"If they don't give us problem, we don't bother," Amoako said. "We're here to serve everybody."

Whether it's obscured by spring snow-storms of Harvard's daily grind, the Square's late-night culture marches on to its funky beats.