bar bars blue cross galvanized geometry gray grid iron matrix metal regular regularity shadow sky steel texture textures zink construction.finish corroded corrosion corrosive crack cracked crackled cracks oxide oxidise oxidize oxidized paint rust rusty surface above abstract angle angled angles architectural architecture ceiling color colored colors colour coloured colours frame framed glass height high light linear lines metal-framework metal-work perspective perspectives shaded shaped shapes silhouettes sky-light skylight skylight-windows structure structured style visibility visible window window-frame windows airy appearances Australia Australian botanic botanic gardens building city contrast craftsmanship decorated decorative Designs detailed distinctive elements exterior external frames framework glass panes glasshouse heritage historic historical hothouse intricate metal work old ornamental panes patterns prestige prestigious protection protective quality structures supports car dew drop droplets drops Morning rain water