recreating Finn MacCool's road to battle

According to legend, the Giant’s Causeway was built by the Irish giant, Finn MacCool, as a crossing to confront his Scottish rival. Scientists have an alternative explanation, and for the first time they have reproduced in the laboratory the process through which the causeway’s 40,000 near-perfect hexagonal columns were formed.
Geometric columns are seen in a variety of volcanic rocks across the Earth and are known to form as the rock cools and contracts, resulting in a regular array of polygonal prisms or columns. But until now, geologists had been unsure of the threshold at which cooling magma suddenly fractures into a geometric pavement.