Abstract We apply dimer diagram techniques to uncover discrete global symmetries in the fields theories on D3-branes at singularities given by general orbifolds of general toric Calabi-Yau threefold singularities. The discrete symmetries are discrete Heisenberg groups. with two Z N generators A. B with commutation AB = C BA. https://www.ealisboa.com/flash-choice-Sten-Jacket-M-flash-find/