function cons(x, y) {
  return function(w) { return w(x, y) };
};

function car(z) {
  return z(function(x, y) { return x });
};

function cdr(z) {
  return z(function(x, y) { return y });
};

var list = cons(1, cons(2, null));

document.writeln( car(list));
document.writeln( car(cdr(list)));
document.writeln( cdr(cdr(list)));