Can you arrange he rings such that each stack of numbers from bottom to top adds to exactly 100?

This is a puzzle from the early 1900's. It is shockingly difficult to solve!  I found the design in Jerry Slocum and Jack Boterman's "New Book of Puzzles". The puzzle was originally made of paper disks riveted together, but I thought it would make a great wood puzzle and it came out quite nice I think.  This is a puzzle that both adults and youngsters down to middle school may enjoy.  It certainly hones your ability to do addition quickly in your head!

I have found 1 solution on my own and thanks to computer work done by Ken Irvine we now know this is the only possible solution!  Ken also determined that there are 7776 different possible combinations that could created with the disks.