As a tangent to How "advanced" can a stone age society get?, is there a way that simple electronics could be created by filling channels cut into rock with some form of conductive material? An organic substance derived from a plant, for instance, or a rare-earth element extracted from seawater.
- Metal and metal-working are unknown or prohibitively rare
- The society itself is quite advanced, and has been able to develop and produce simple computers using purely mechanical means.
- Earth's plant and animal life. (No new hypothetical kinds of plants and animals, but more extreme species of earth organisms could be postulated)
- The society knows how to selectively breed desired traits into plants and animals easily, allowing for more extremely specialized versions of current earth organisms.