Changes to Partial Scene Lecture

• 2021-11-16 12:51:46 UTC (Hans Georg Schaathun): OK THursday lecture
• 2021-11-16 11:47:23 UTC (Hans Georg Schaathun): Added exercise.
• 2021-11-15 10:28:12 UTC (Hans Georg Schaathun): categories
• 2021-11-15 10:27:27 UTC (georg): stub