redundancy

packet1 =
  sum{i in 1..7} x[i];

packet2 =
  sum{i in 1..7} f[i,x[i]];

packet3 =
  sum{i in 1..7} g[i,x[i]];

packet4 =
  sum{i in 1..7} h[i,x[i]];

(1,f) - ok
(1,g) - ok
(1,h) - ok

(f,g)   - ok
(1,f,g) - ok

(f,h)   - ok
(1,f,h) - ok

(g,h)   - ok
(1,g,h) - ok
28224 valid combinations so far

(f,g,h) - failed, none of 28224 is ok

* * *