And now is an appropriate time to delve into this enigma wrapped in a flatbread. A cheap meal looks pretty appealing lately, and more people than ever seem to be succumbing to this $5 temptation.

While almost all segments of the restaurant industry are suffering, the titans of the gyro  all of them based in Chicago  report that sales are either steady or way up.

These companies are private, so their word will have to do. But Kronos is preparing to move to a new plant that will enable it to crank out enough cones for 600,000 sandwiches a day, about twice the capacity in its current address. A few miles away, at Devanco Foods, Peter Bartzis, the president of the company, reports record sales. “I’ve been through a few recessions,” Mr. Bartzis said, “and they’re good times to be in the gyros business.”

Mr. Tomaras opened Kronos in 1975 and sold it to a private equity firm in 1994. But he returned to the plant, on a dead-end industrial road in Chicago’s southwest side, to explain how gyros are made. It’s a show and tell that is not for the squeamish.

The process starts with boxes of raw beef and lamb trimmings, and ends with what looks like oversized Popsicles the shade of a Band-Aid. In between, the meat is run through a four-ton grinder, where bread crumbs, water, oregano and other seasonings are added. A clumpy paste emerges and is squeezed into a machine that checks for metal and bone. (“You can never be too careful,” Mr. Tomaras said.) Hydraulic pressure  60 pounds per square inch  is used to fuse the meat into cylinders, which are stacked on trays and then rolled into a flash freezer, where the temperature is 20 degrees below zero.