/// `gf1.set` and `gf1.get` were created within the same call to
/// `makeAccessors`, so they see the same `x`.  `gf1.set` and `gf2.set`
/// were created within different calls, so they see different `x`'s.
function makeAccessors() {
    var x;
    return {get: function() { return x; },
            set: function(y) { x = y; }}
}var gf1 = makeAccessors();
var gf2 = makeAccessors();
gf1.set(10);
gf2.set(20);
log(gf1.get());
log(gf2.get());