Stack sugar枯山水

Quick answer：

Stack sugar is a creative way to refer to the traditional Japanese Zen garden style known as Karesansui, which translates to 'dried landscape'. Karesansui is a minimalist form of Japanese rock garden that emphasizes the use of rock, sand, and often moss to represent a natural landscape in a simplified manner. It is often used in Zen Buddhist temples and has become a popular artistic expression in modern times.