In the 1770s, while the Qianlong Garden was being built, Europeans and other interested trading partners introduced foreign technologies and art forms to China. Mechanical clocks, glass, mirrors, trompe-l'oeil murals, differently colored glazes and paint, enamels, and even Japanese-style lacquer all appealed to the Qianlong Emperor's cosmopolitan aesthetic interests. He thus incorporated foreign styles and materials into the garden's interiors, using them to express traditional Chinese ideals or to facilitate further self-cultivation. For instance, he noted that he enjoyed gazing through glass windows at the rockeries in the garden, imagining himself living in a mountain abode. A number of spaces in the garden were outfitted with exotic furnishings imported from or inspired by non-Chinese sources.