“…Our basis was made by the following 17 loops (called tetrises for short) 3 : , , , , , , , , , , , , , , The same process can be applied to the other spin/parity channels; in these cases, however, one has to choose loop shapes not completely invariant under dihedral symmetry, and then construct proper linear combinations of the differently oriented copies of them. This approach has been successfully applied to the 3D Ising model spectrum in [2]. Example of observables constructed this way are:…”