It is a flat, perforated rectangular stone, roughly 35cm tall and 40cm wide, with three tear-shaped holes arranged at its centre in a triskele pattern, a three-armed rotational design with early medieval associations. The left-hand portion of the stone is missing; when complete, it would have measured at least 50cm across. Whether it once served as a small window or a ventilation opening is uncertain, and its exact origin is unknown, though it may well have come from the church of St Patrick directly across the road. Comparable triskele stones are known from at least two other Irish sites, including examples at Coole near Ferbane and one from Taghshinny near Ballymahon in Co. Longford, which suggests the type had some currency in medieval Irish ecclesiastical building.

The shed stone is only one piece of a much larger, somewhat scattered puzzle. In the vicinity of St Patrick's Church, at least fifty fragments of medieval masonry survive, the majority of them window tracery. Some have been stacked at the west end of the medieval chancel, others lie beneath table tombs in the graveyard, and several decorated pieces have been placed in the vestibule of the tower. Among them are window mullions carved in relief with undulating branches of ivy and oak leaves, pieces of doorjambs and capitals, gable fragments, and part of a carved stone drain or gutter. A number of ogee-headed window openings, one of them at least triple-light, can also be identified in the collection. Worked sandstone blocks from the same pool of salvaged material were incorporated into the tower's west door. Some of this material appears to have been drawn in from further afield: a nineteenth-century source records that tomb remains and a carved doorway from Newtown Trim were inserted into the church porch, and a man named Butler brought decorated medieval floor-tiles from both Bective and Newtown Trim to St Patrick's, placing them in the vestry wall. Those tiles were still recorded as present in 1906, but had disappeared by 2005. Butler also made use of a blocked doorway in the west wall of the nave to insert a piscina, a small stone basin used for disposing of water blessed during Mass, into the new wall surface.