Today I found something interesting. I was practicing a lesson from the Gregg Simplified Manual, 1st Edition (paragraphs 431-433, page 227-230), transcribing it into Anniv Gregg. I noticed that I have read this same material before. Lo and behold, I found the material in three places, in the 2d edition of the Simplified Manual (paragraphs 551-553, pages 307-309), in the 1st Edition of the DJS manual (Lesson 69), and in the Series 90 manual (paragraphs 611-613, pages 306-308)! Save for a few words here and there, the paragraphs are virtually the same.
If you are curious about the content, the paragraphs represent an exchange between a hotel and a guest, in which the housekeeper, while cleaning, noticed that blankets were missing from the room. The hotel is asking the guest to return them to the hotel. Between versions, that the cost of the blankets went from $8.00 (Simplified) to $40.00 each (Series 90).
I wonder how many other recycled paragraphs are there between the versions.