Follow-up on our experimentation with popsicle-stick structures and longsword locks: Walter Whiteley's related article

 Hi everyone! Here's the link to Walter Whiteley's 1989 research geometry article on  'Rigidity and
Polarity II' -- the article that George Hart referred to in his film on the geometry of longsword locks. If you're looking for the algebra related to longsword locks, you'll find it here (albeit at a level that is quite specialized mathematically!)

From an educational point of view, you might be interested in Walter Whiteley's work on mathematics education and geometric/ spatial reasoning -- like this one, for just one of several examples!