# Define 2-tuples
pair a b fn = fn a b;
first p = p true;
second p = p false;

# Define Church encoded lists in one-pair-as-a-list-node style
cons = pair;
head = first;
tail = second;
nil = false;
_a x y z = false;
isnil l = l _a true;

# Test them out
list1 = cons "1" nil;
list2 = cons "2" list1;
list3 = cons "3" list2;