generators.tdTransducer("copying"):
( { a:0, b:0, c:1, h:2, v:2 },
  { a:0, b:0, c:1, h:2, v:2 },
  { cp, id },
  { cp[c[x1]] -> h[c[id[x1]],c[id[x1]]],
    cp[h[x1,x2]] -> h[h[id[x1],id[x2]],h[id[x1],id[x2]]],
    cp[v[x1,x2]] -> h[v[id[x1],id[x2]],v[id[x1],id[x2]]],
    cp[a] -> h[a,a],
    cp[b] -> h[b,b],
    
    id[a] -> a,
    id[b] -> b,
    id[c[x1]] -> c[id[x1]],
    id[h[x1,x2]] -> h[id[x1],id[x2]],
    id[v[x1,x2]] -> v[id[x1],id[x2]]
  },
  cp )
