Details of the final axial sections across the morphological fronts for the GD15, GA15 and GA11 experiments. The roman numerals indicate the order in which the faults appear. (a) Illustration of a synthetic versus an antithetic fault. (b) Illustration of faults formed in sequence. (c) Illustration of faults formed out of sequence. The black arrows on the right-hand side indicate the sliding direction. The roman numerals give the order of occurrence of the faults.