Here is the implementation of the Decimal to Binary Encoder from the book. They used an empty thread spool, wrapped it with uninsulated wire, then covered the wire with paper that had cutouts for the binary codes. Four paperclips were used as contacts to read the codes (I told you there would be paperclips). It was an ingenious design using only the promised household items.

Here is my implementation:

While my design does not use paperclips, I believe it embodies both the concept and spirit of the original. I'm not going for a "pure" replica here. At the end of the day someone should be able to operate the new machine from the instructions in the book, starting with the Decimal to Binary Encoder.

For more details I published my Mostly 3D Printed Binary Encoder design to Instructables.