There is an identity symmetry (rotation by 0 degrees) that acts just as the number zero acts in our number system. And every symmetry can be undone, just as adding 3 can be undone by adding –3: For ...

Now we introduce symmetry by rearranging the field of Bistable Quartets to form a “butterfly” pattern, which is bilaterally symmetric across the vertical axis.

They all have vertical symmetry. This means you can draw a mirror line down through the middle of each shape and divide it into two reflected halves. Remember vertical means from top to bottom. It ...