abstract angled angles appearance background basic color colour concrete curved curves curving external footpath gray grey grooved grooves ground hard-surface hard-surfacing lined lines mottled mottling outdoors outside path pavement paving perspectives rough streaked streaks surface surfaced surfaces texture textured textures variations crazy-paving Designs detailed detailing distinctive gaps haphazard irregular level light mortar patterns pavers shaped shapes size Sizes smooth stones stonework uneven striations colored colors coloured colours fired glazed glazing hard layered layers lumps lumpy molten pottery surfacing thick thin