Si Fang (Zhu) Xi Xiang 四方(竹)席香, by L4 Assoc Master Artist Shen Ji Yang 沈继扬

Exhibits curve in construction.

Each edge exhibits a curve in two planes, either X-Y, or X-Z, or Y-Z planes.

And how Shen Ji Yang does all of this, and yet maintaining the neatness and squareness of all the neat perpendicular matting of the bamboo stripes, is amazing.