Much like people still use fungus riddled Diamond Willow to make walking sticks and other items, spalted wood was also a part of the art of Intarsia, a specific type of wood inlay. Here are a few stunning examples, and you can see and read much more about the history of this art at the Public Domain Review.
The technique of Intarsia — the fitting together of pieces of intricately cut wood to make often complex images — has produced some of the most awe-inspiring pieces of Renaissance craftsmanship.
Note: if you click over to the Met Museum, the way to see the images full size is to click on ‘download’. All the images here, click for full size!

Detail from an intarsia piece by Fra Damiano da Bergamo, early 16th century. Note the subtle dots of greenish-blue in the covered archway — Source.

Those “cupboards” are trompe l’oeil! Part of the Studiolo Gubbio as installed in the Metropolitan Museum — Source.

Scipio Africanus (ca. 1425–30), intarsia by Mattia di Nanni di Stefano using poplar, bog oak and other wood inlay, rosewood, tin, bone, traces of green colouring — Source.