The Italian furniture makers at Promemoria are known for their inventive uses of materials, such as the caramel-colored ash wood that the company treated—and turned gray—for its Belvedere chaise (see “Taking It Outside” in Robb Report Home & Style’s March/April issue). Promemoria’s innovative approach to home decor will be on display next week in Milan at the Salone Internazionale del Mobile, where the company will introduce 25 new pieces, including the Bip Bip side table (shown), which is made from cast b…