Polygon Symmetry
Rotate and reflect regular polygons
Dihedral Triangle
Transform a triangle, build the table
Same Paper
Draw once, then add the rotations and reflections that repeat it.
Braid Diagram
Build a braid, simplify it, save it as SVG, PNG, TikZ or LaTeX
Braid Tangle
Dance a tangle and watch the same moves braid under a cap
Sandpile
Drop grains on a grid, watch cells topple.
Hex Sandpile
Drop grains on a hexagonal grid where cells topple at six.
Necklaces
Color a ring of beads, cut it into a strand.