L6a3 Further Notes and Views

Ruberman, Cochran, Melvin, Akbulut, Gompf, Kirby [1]

Rich Schwartz' "72" [2]

Triangle interlaced with a circle, a traditional symbol of the Christian Trinity (less used in recent centuries)

An architectural trefoil (the outline of three overlapping circles) interlaced with an equilateral triangle, another old Christian Trinitarian symbol.

Further images...   

Double boomerang like Kolam and Linked knot, Nagata.