Updates of notebooks 3 & 4
This PR includes a few fixes and preliminary updates to notebooks 3 and 4. I started to clean up the notebooks and these also now include the same coloring and cell locks as introduced for notebook 2.
This PR includes a few fixes and preliminary updates to notebooks 3 and 4. I started to clean up the notebooks and these also now include the same coloring and cell locks as introduced for notebook 2.