Art Nouveau made use of many technological innovations of the late 19th century, especially the broad use of exposed iron and large, irregularly shaped pieces of glass in architecture. The style was richly ornamental and asymmetrical, characterized by a whiplash linearity of syncopated rhythm, reminiscent of twining plant tendrils. Its exponents chose themes fraught with symbolism, frequently of an erotic nature. They imbued their designs with dreamlike and exotic forms.