Special Containment Procedures: SCP-XXX is to be kept in a metal storage locker measuring 20 cm × 20 cm × 20 cm. The locker is to be built using only incredibly precise right angles (π/2 rad, +/- π/256 rad), but otherwise no special containment procedures are required.
Description: SCP-XXX is an antique carpenter's square, measuring approx. 14 cm to a side. The square has a brass support brace, and is composed of an unidentified wood similar in composition to pine, with inch markers as well as several auxiliary marking sets.
When placed on top of an angled object, or two adjoining objects, SCP-XXX will quickly force a perfect right angle. High-speed camera footage shows the process taking no more than ██ milliseconds, and a correlation has been found between the tensile strength of an object's material and the speed of SCP-XXX. The method that it uses to accomplish its "adjustments" is currently unknown.
Retrieval Log: SCP-XXX was found in the workshop of a master carpenter who was known locally for high quality furniture and incredible assembly speed. Authorities were alerted when the carpenter, an old man in his 80s, was found with his spine in a right angle, the joint forming between the 6th and 7th thoracic vertebrae; cause of death was determined to be blood loss and internal trauma. SCP-XXX was found resting directly above this joint.