architecture barcelona color colors colour colours floor guell Spain tiles tiling wall gaudi abstract appearance background bright checkered coloration colored colorful coloring coloured colourful colouring decorative design details floor-tiling horizontal interconnected interlinked interwoven light linear lined lines matrix mosaic patterns perspectives row rows shape shaped shapes small square squared squares style surface surfaces surfacing texture textured textures vertical vibrant wallpaper brown cream creased creases depth patterned pieces purple purple-centred