WILLIAMSBURG, Va. — Decades ago a simple wooden board in use as a shelf was discovered in Belle Farm, an 18th-century house in Gloucester County, Virginia. It turned out to be much more interesting than an untrained eye would notice at first glance: etched into the surface was the original design for two arches that are still to be seen in the house today. This extraordinary artifact provided Colonial Williamsburg’s architectural historians with valuable information on design development and layout in the last half of the 1700s. The design was later used as the model for the arches in the southwest dining room of the reconstructed King’s Arms Tavern on Colonial Williamsburg’s Duke of Gloucester Street.