This screenshot from the Eye of the Beholder game shows a similar style that Rick used. Especially for the columns have a similar gradient with squiggly veins and top/bottom bases.
The color palette for this image is also organized quite curiously. Rick created most of his Amiga artwork in EHB mode, but Eye of the Beholder organizes the colors in groups of hues, 16 colors apart.
This was done to make the game EGA compatible, because you could just take the 256 color image and truncate the upper 4 bit of each pixels palette index, which would then automatically result in a 16 color image that would still look fairly good.
Impressive technique, but quite wasteful, as can be seen by the amount of white (empty) palette entries.