The top two rows show differential surface error maps at different progressive time instances obtained using the multi-tool multiplexing simulation (cumulated total dwell time runs from 1 through 6, note the changing scalebar), bringing down the initial (i.e., total dwell time = 0 h) surface figure error of 2210 nm RMS to 7.9 nm RMS using four tools simultaneously. The bottom row shows the tool path (left), final surface error map (middle), and time evolution of the CCOS run parameters (right).