This is quite a mathematical corner of Stirlingshire , cup marks come in pairs e.g. the pair of "spectacles" the same stone had another pair of cups as had a new one with two pairs. The triangular shaped stone has cups at the bottom right and was probably once part of the erratic close by . It is an equilateral triangle , sides of 1.2m and mirrors Ben More in the background . I doubt any self respecting megalith builder would be as crass as to erect something so Pythagorean so I assume it was done quite recently , past 2000yrs approx. The "dolmen" is in the past 20 yrs .