accommodation apartment blocks apartments Asia balconies balcony buildings condominiums condos costly expensive flats high-rise living areas multi-storey multi-story Singapore units valuable wealth wealthy homes washing washing poles windows curved Dirt discoloration discolored discolouration discoloured rounded angled angles apartment-blocks appearance architectural architecture barrier barriers building concrete ghrills gray grey grill grille grilles living-areas metal plants potplants potted-plants railing safety shade shaded shelter sheltered steel