A drunkard’s walk through scrambling space. Ovals show possible configurations for a gene with just 3 MDS segments A, B and C. Inverted segments are shown in lower-case (e.g., inverting block AB converts ABC into baC). Lines between ovals represent evolutionary paths (mutation-fixation events) from one configuration to another. The figure shows only inversion paths; considering translocations would add some new pathways (e.g., a link from ABC to BAC), but no new configurations. This graph (minus the drunkard) was computed automatically by a Perl script (available as Additional file 1) and plotted with GraphViz.