A mathematical framework is proposed to predict the features of the (5 5 7) lath transformation in low-carbon steels based on energy minimisation. This theory generates a one-parameter family of possible habit plane normals and a selection mechanism then identifies the (5 5 7) normals as those arising from a deformation with small atomic movement and maximal compatibility. While the c... https://www.roneverhart.com/Oakley-Fives-4-0/