At three in the morning in February, Massachusetts Avenue belongs to the plows and nobody else — shop windows dark past Depot Square, snow coming sideways under the streetlights. CarrollBrothersinc runs those hours, plowing driveways and clearing walks so that by the time Lexington wakes the storm looks like it happened somewhere else. Nor'easters here arrive wet and heavy and set up hard by dawn, which is why the timing of a push counts as much as the push. Nothing beats backing out of a drive at first light with the whole apron open to the street and the banks stacked well out of the way. Then on to the next house, coffee later.