beam blick block cantilever concrete construction cutout isolated part bare brown clean divided sidewalk Spacer wood arch bridge canyon croatia Krka river Skradin abstract bodgie decay rust texture background build lastrico pattern terazzo textures wall appearance base blocks circular concrete-work cracked cracks damage damaged dark dirty foundation-work foundational foundations gray grey greyscale grime historical old past raised remainder remaining reminder round solid structure architecture barrier city London staircase stairs steel urban autumn Blätter colours fall Herbst leaves yellow green grow moss nature organic plant surface