An H-tree is formed in a conducting layer over a base array of a structured ASIC, the H-tree being a predefined constraint imposed on ad hoc circuit designs adapted to make use of a base array and H-tree. The endpoints of an H-tree can be formed at or near sequential elements. When an H-tree is used as part of a clock structure, clock skew to sequential elements and consumption of routing resources for forming a clock structure can be minimized. When a pulse generator is coupled to an H-tree, at least one flip-flop of a plurality of flip-flops can be emulated with an individual latch, thereby increasing effective flip-flop density.