12.1-12.2, due on November 15

1. (Difficult) I think the basic idea is intuitive.  Give two people equations for a line, and the secret is the point at which their lines meet.  I didn't follow all of the specific math though.  The example was helpful, and I think I could apply the equations to solve a problem.  I think with sufficient effort I could understand the ideas pretty well, based on what we learned in linear algebra.  Hopefully I'll pick up more of the intuition in lecture.
2. (Reflective) I recall reading or hearing about papers (or a paper?) mentioning that such thresholding schemes were possible.  I suppose they may have referred to some of the work referred to by the sections we read.  Is this question still being worked on, or is it pretty much a solved problem?  Are there any every-day uses of these ideas for cryptography?