In a recent Nature Communications study, researchers have reported the realization of an anti-spin ice, a system that does the opposite of conventional spin ices by breaking the ice rule that governs them.

Spin ices are magnetic systems that mimic a rule found in water ice. In water ice, each oxygen atom keeps two hydrogen atoms close and two farther away. This is known as the ice rule. Because many arrangements satisfy this rule equally well, the hydrogen atoms in ice end up being disordered, meaning that there’s no repeating pattern.

This is a sign of geometric frustration, which occurs when competing interactions in a system can’t all be satisfied at once, leaving many equally good compromises.