more objectish things

```racket
(def (make-fish sz)
  (let ()
    (describe my-fish
              [size sz]
              [get-size (fn () size)]
              [grow (fn (amt)
                      (Self `(,(+ amt size))))]
              [eat (fn (other-fish)
                     (grow (other-fish 'get-size)))])
    my-fish))
(def charlie (make-fish 10))
(check-equal? (charlie 'size) 10)
(def charlie2 (send charlie 'grow 6))
(check-equal? (charlie2 'size) 16)
(check-equal? (send charlie2 'get-size) 16)
```