Step 3: The two active points from Step 2 spawn new optimizations toward each of their neighbors. Two such constrained optimizations expand to the left and right, resulting in new active grid points at -120 • and 120 • . The other two constrained optimization are both targeted at the grid point at 0 • , thus the grid point at 0 • gains two new sets of geometries and energies, which are potentially better (lower in energy), equal, or worse (higher in energy) compared to the existing data. To determine which data to keep, we compare the energy of each new result with the current lowest energy at this grid point. In this example we assume both new optimization results are equal to or higher than the energy obtained from the original optimization in Step 1. In such cases, the grid point is marked as inactive (blue).