.. Moiré effect ...

Thank you, of course, Moiré effect. I couldn't for my life remember the name of the effect. The origin of the pattern is just a phone picture of a wall as a part of the decision whether just to paint or tear down the panel. Small section of image cropped and edited with the Gimp.

Such patterns can be useful, small in size and can be stretched, skewed and colourized to produce a variety of structured surfaces in SH3D.

ok

Stretched... ..and a bit more: