T(x) = y T(y) = xy

This transformation has the following successive effect (starting with x):

x ⇒ T(x) = y y ⇒ T(y) = xy xy ⇒ T(x)T(y) = yxy yxy ⇒ T(y)T(x)T(y) = xyyxy xyyxy ⇒ T(x)T(y)T(y)T(x)T(y) = ...