Flexagons - a beginning thread
Another thread - 1-period paper folding
More paper folding threads - 2-period paper-folding
A number-theory thread - folding numbers, a number trick, and some titbits
The polyhedron thread - building some polyhedra and defining a regular polyhedron
Constructing dipyramids and rotating rings from straight strips of triangles
Continuing the paper-folding and number-theory threads
A geometry and algebra thread - constructing, and using, Jennifer's puzzle
A polyhedral geometry thread - constructing braided Platonic solids and other woven polyhedra
Combinatorial and symmetry threads
Some golden threads - constructing more dodecahedra
More combinatorial threads - Collapsoids
Group theory - the faces of the trihexaflexagon
Combinatorial and group-theoretical threads - extended face planes of the Platonic solids
A historical thread - Involving the Euler characteristic, Descartes' total angular defect, and Pólya's dream
Tying some loose ends together - Symmetry, group theory, homologues, and the Pólya enumeration theorem
Returning to the number-theory thread - Generalized quasi-order and coach theorems.