On the Nok plateau, the people learned to ask the earth for iron. They built furnaces tall as a man, shaped like the lung of a great beast. They fed them charcoal. They pumped air through goatskin bellows — two boys squeezing in rhythm, like a heartbeat — and the red earth wept iron.

This was the first engine. Not a machine. A furnace, a song, and hands that knew the color of fire.

In the palace of the Oba of Benin, a guild kept a secret older than the kingdom. A man would carve a face into beeswax — every line, every coil. He would pack it in clay and put it in the fire. The wax would melt and run away. Into the empty place it left, they poured molten brass.

When the clay was broken open, the face was there. The wax was gone. The face remained.

In Timbuktu, a king named Mansa Musa had so much gold he could have made himself a god. He built a library instead. He called it Sankore. Twenty-five thousand students in a city of a hundred thousand. One man in four, a scholar.

The story goes that he said: gold buried in the ground is only gold. Gold that becomes knowledge becomes light. And light does not stay in one place.

Sankofa. Go back and fetch it. There is no shame in returning for what was left behind.

We returned for three things. The furnace of the Nok — we call it the turbine now. The foundry of the Oba — we call it the gear. The library of Mansa Musa — we call it the circuit.

Three fires. One engine. Woven into the cloth.