I don't know what book code is but I think it likely we'll either all be safe or none of us will.
Really? You're older than me.
Two people have the same book with the same printing issue number. Ex. Hitchhiker's Guide to the Galaxy with printing number 8. This means both books have the identical type facing for page layouts page by page, line by line and word for word.
One person goes through the book randomly selecting pages, lines, and words. On a sheet of paper, the person writes three columns of numbers. 1st number is page. 2nd number is line from the top of page. 3rd number is word from the left side of line.
Each 3 number set on horizontal line is selected word.
2nd person finds secret place for note and uses 2nd copy of book to translate onto another piece of paper.
Basic setup. Initial setup agreement can be altered with number set be mixed in page, line, and word position. Also, line is from top or bottom of page. Plus, word can be from left or right side of line.
Advanced code includes ciphers. 1st person places a written instruction into coded message, usually "shift up, shift down, shift left, shift right" followed by a number. This tells the 2nd person to respond with new coded message number sets reflecting the change in number. Up and down refer to number value and left and right refer to page, line and word placement. The first person reads coded message and makes the necessary adjustment for actual message.
Stuff I learned in Elementary School. By the 6th grade, you mastered both book code and igpay atinlay. The secret languages of children.
