From Shelby Foote’s The Civil War: Fort Sumter to Perryville (399):
No wheeze was too old for [John Bankhead] Magruder to employ it. One morning he sent a column along a road that was heavily wooded except for a single gap in plain view of the enemy outposts. All day the gray files swept past in seemingly endless array, an army gathering in thousands among the pines for an offensive. They were no such thing, of course. Like a low-budgeted theatrical director producing the effect with an army of supernumeraries, Magruder was marching a single battalion round and around, past the gap, then around under cover, and past the gap again.