The construction of masonry paving involves using materials such as bricks, stones, and concrete masonry units. These materials are chosen for their shape, color, strength, and resistance to abrasion and weathering. Masonry units can be installed dry on a thin layer of sand and a gravel base, or they can be embedded in mortar or asphalt on a concrete slab. For areas subjected to heavy vehicular loads, a rigid base layer of reinforced or unreinforced concrete is recommended. In contrast, pedestrian pathways often use a semi-flexible base of asphalt or bituminous concrete or a flexible base of gravel or sand. The setting bed, a layer sandwiched between the paving units and the base layer, is typically 1-2 inches thick and consists of pea gravel or finely crushed stone. Its primary function is to level irregularities in the base or in the units themselves. A modern feature in paving is the permeable paving system, designed to allow rainwater to pass through the pavement and infiltrate the underlying soil. This feature is achieved using porous materials such as pervious paving blocks or by designing spaces between conventional paving units filled with sand or vegetated soil. Such systems help reduce the burden on municipal drainage systems and contribute to groundwater replenishment.