Let W be a sector, let w <- W be an element, and let e : W -> W be a calc. The *unary shift relay with germ* w and *protocol* e is the sequence

$$w,e(w), e^w(e(w)), e^{we(w)}(e^w(e(w))),...$$

where e : W -> W is a calc and W is a sector.

An n-ary shift relay of calcs is _.