A long, long time ago, Publius Syrus said that to do two things at once is to do neither. Sorry, Pub, but having visited the Flying Saucer Pie Company, we strongly disagree. Since 1967, co-owners Bill Leeson and Marilyn Smith have been doing at least a dozen things at once, each one of them brilliantly. Cherry, coconut cream, pecan, fresh strawberry cream, pumpkin, key lime, chocolate cream...Maybe their loophole is that they do pies and pies alone -- no sandwiches, no tables, no drinks. No matter. On Tuesday through Saturday mornings at 8 a.m., Flying Saucer's legions of loyal customers line up at the modest Garden Oaks-area store to get a whiff of the tantalizing aroma of baking and take home a perfect pie (or two) straight from the oven.