Technology
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Left we can see how technology developed incrementally: the familiar baking-oven has been enlarged and modified into a high-temperature kiln for firing pottery. Agricultural societies world-wide have discovered that "baking" clay in extremely hot fires for a long period creates hard, durable objects such as the plates, jugs, and pots above. These examples are from 'Ubaid' culture in Mesopotamia, one of the earliest pottery-making societies. Another step in a sequence of technological development was the modification of the pottery kiln into a furnace capable of melting metal ores (below).
Note that the earliest forms of furnaces for smelting ores at left above even retain the form of the mud oven. Over time, smelting ores became a highly refined technology and furnaces evolved into new forms.