what does the equilateral triangle symbolise in the mark degree and where does that reading come from

The claim that an equilateral triangle served as a mark of approval in operative masonry is apocryphal, carrying no historical sanction or foundation in the practice of the operative craft 1. Mackey observes that no masonic marks have been identified on ancient Jewish buildings or King Solomon's Temple, treating narratives that ascribe this function to the triangle as unhistorical inventions rather than genuine operative carryovers 1.

Furthermore, ritual accounts depicting a workman suffering for presenting a triangle in place of his own mark misrepresent traditional operative customs 1. Beyond establishing that the triangle's alleged origin as an operative mark of approval is legendary, the supplied source material does not set out a positive speculative or moral interpretation of the emblem 1.

The available sources do not record the specific individual who first gave the equilateral triangle the interpretation of a mark of approval. Mackey describes the narrative as an apocryphal story and a fad introduced by unnamed theorists, noting that such a regulation has no foundation or sanction in the historical practice of the operative craft 1.