Crazy paving is a means of hard-surfacing

Pavement (material)

Road surface or pavement is the durable surface material laid down on an area intended to sustain vehicular or foot traffic, such as a road or walkway. In the past cobblestones and granite setts were extensively used, but these surfaces have mostly been replaced by asphalt or concrete. Such...

 used outdoors, most frequently in gardens. Paving stones of irregular size and shape are laid in a haphazard manner sometimes with mortar

Mortar (masonry)

Mortar is a workable paste used to bind construction blocks together and fill the gaps between them. The blocks may be stone, brick, cinder blocks, etc. Mortar becomes hard when it sets, resulting in a rigid aggregate structure. Modern mortars are typically made from a mixture of sand, a binder...

 filling the gaps between. The method originated in Ancient Rome

Ancient Rome

Ancient Rome was a thriving civilization that grew on the Italian Peninsula as early as the 8th century BC. Located along the Mediterranean Sea and centered on the city of Rome, it expanded to one of the largest empires in the ancient world....

.

The term may also refer to a pattern seen on computed tomography

Computed tomography

X-ray computed tomography or Computer tomography , is a medical imaging method employing tomography created by computer processing...

of the chest, involving lobular septal thickening with variable alveolar filling.