(VAR x y)
(RULES
f(x,y) -> g1(x,x,y)
f(x,y) -> g1(y,x,x)
f(x,y) -> g2(x,y,y)
f(x,y) -> g2(y,y,x)
g1(x,x,y) -> h(x,y)
g1(y,x,x) -> h(x,y)
g2(x,y,y) -> h(x,y)
g2(y,y,x) -> h(x,y)
h(x,x) -> x
)
(COMMENT Example 4 (TRS $\RR_2$) in \cite{O95})