Rosie saw Tallie look up from the mushrooms. She was frowning.
The Book explained. "You and I have a common problem: it follows that we may share in its solution. Each of us needs to analyze the output from a mechanism. As it happens, part of the solution is already built into my works. You can reproduce that mechanism quite easily, I think. The remainder of the solution is a commercial device. I know what that device is, and where it can be purchased. All that remains is to connect the two together with a certain amount of ingenuity."
Rosie thought that over. "I may have lost count, but that sounds like one service. You mentioned two."
The Book waved its hands. "Oh, a triviality. It is of little consequence. I also need another simple machine." It gestured around at its spinning gears and cams. "I am able to extend my own mechanism, of course, but this is a different matter."
"It's a little bit scary," said Rosie, "to think that you can modify your own works."
A set of televideo screens scissored down from overhead on big copper mounts. The Book indicated them. "I am, as you see, a revised edition."