The interior design firm BHDM broke the vanilla rule at a model unit for the Ashland in Brooklyn. Credit Adam Macchia/Gotham.

“Through color and personality, and non-vanilla spaces, we’re setting the things for people to remember,” said Dan Mazzarini, a partner in the interior design firm BHDM, which designed five model apartments at the Ashland. The 585-unit rental building at 250 Ashland Place in Brooklyn offers studio to three-bedroom apartments ranging from $2,675 to $7,500 a month.

One of the model units has dazzling colors and patterns, including walls with painted trompe l’oeil paneling, powder-blue ceilings and counter stools, and a purply pink tie-dye rug.

“When renters are going around to all these new buildings, they’re seeing maybe 10 units a day and it’s hard to remember, from one white apartment to another, which they liked and why,” Mr. Mazzarini said. “So we built these memory points — it’s the unit with the pink rug, or the 12-foot sofa, or the hats on the wall.”