<article> # Illustration of Case 2.1 $ (b = s) $ (no intersection) ## Initial <pre style="text-align: left; margin: 0 auto; display: inline-block;"> • • • • <span style="color: cyan">•</span> • • • <span style="color: cyan">•</span> <span style="color: cyan">• •</span> </pre> ## Operation A: Permissible <pre style="text-align: left; margin: 0 auto; display: inline-block;"> • • • • <span style="color: cyan">• •</span> • • • <span style="color: cyan">• •</span> </pre> ## Operation B: Not Permissible <pre style="text-align: left; margin: 0 auto; display: inline-block;"> • • • • • • • <span style="color: cyan">• •</span> <span style="color: cyan">• •</span> </pre> </article>