Finally finished the puzzle (aoc day 7 2015); I firmly believe that the circuit can do a whole lot more than what is described in the puzzle text

advent_of_code/2015/7/test.txt

@@ -0,0 +1,8 @@
+123 -> x
+456 -> y
+x AND y -> d
+x OR y -> e
+x LSHIFT 2 -> f
+y RSHIFT 2 -> g
+NOT x -> h
+NOT y -> i