This is a regular geometric pattern etched onto the surface of the tungsten.

ECONOMIST: Solar power

The researchers in this study examined the geometric structure and behaviour of one of the rotavirus's surface proteins, called VP4, which plays a key role in binding on to the surface of a target cell, and breaking through its membrane.

BBC: NEWS | Health | Diarrhoea vaccine 'a step closer'

It recommended using geometric lines of latitude and longitude to convey a three-dimensional Earth on a two-dimensional surface, and it included the co-ordinates of over 8, 000 locations in the ancient world.

ECONOMIST: There is no such thing as an objective map