The One Where Rachel Smokes - S5-E18
Continuity mistake: Joey's snowcone changes during the scene with Ross at the party. It goes from rounded to more flat to rounded, and from plain ice to being able to see the flavoring to ice again. (00:20:00)
The One Where Rachel Smokes - S5-E18
Continuity mistake: When Ben is playing with the building blocks, they change with each shot, and he holds different coloured blocks each time. (00:15:20)
Answer: The painting doesn't have a name, and if it does it is never mentioned in this episode.