A video aired by BBC last year shows how sections of the face grow and fit together like a puzzle just three months after conception.

The animation is based on scans of a developing embryo and captures the formation of the face in the womb.

According to the Daily Mail, the 30-second clip strings together 3-D models of the developing face based on scans taken in the first trimester.

“It was a nightmare for structures like the nose and palate, which didn’t exist for most of the animation,” graphics researcher David Barker was quoted as telling New Scientist.

“Their formation is a complicated ballet of growth and fusion of moving plates of tissue.”

Plates of tissue that fuse at the philtrum, which can be long or short and deep or shallow, depending on a person’s genetic makeup.

The failure of those plates to fuse can cause a cleft lip or palate. And a smooth philtrum can signal disorders like fetal alcohol syndrome.

“This whole amazing process – the bits coming together to produce a recognisable human face – happens in the womb between two and three months,” said Mr Mosley. “If it doesn’t happen then, it never will.”