Scribble -- numbered exercises across multiple files in HtDP

[ericj...@gmail.com]

I'm curious to learn how the authors of HtDP were able to create numbered exercises that spanned multiple files.

From reading the low-level Scribble API I'm guessing these were made with delayed-content or delayed-block, but I am having a hard time understanding the intricacies of the API.

If someone could show me how to do this or point me in the right direction, I'd be very grateful. Thanks!