Today, I combine my two favorite topics: symmetry and Celtic knots.
I use symmetry to design my tessellation quilts. I can also use symmetry to design Celtic knots.
Take this loop-the-loop for example.

If I rotate three copies around the center of the loop, I get this:

If I rotate three copies off center, I get this:

I can line loops in a row, like this:

I can cover an entire surface, like this:

What next??