Here are some ideas how to use different widths of 3,4,5 and 6cm for the elements of the sound diffusors to obtain optically symmetrical devices which might by more appropriate for living rooms. The Colors refer to the different widths used for the elements: Brown : 6cm,  Yellow : 5 cm,   Green : 4 cm,   Blue : 3 cm

Some of the designs have different corners which indicates 4 proposed versions in one image. When using them for acoustic purposes, they should be used in a way to finally cause symmetry by either choosing one pattern for all corners or use 4 such modules in mirrored versions.