Week 11: wikipedia part 3 "koch" "sprial"

This week we study two main orders: koch and sprial.
For the second part of "koch", we need to write one check-expect
(check-expect (koch-snowflake 2)
(above
(beside
(rotate 60 (koch 2))
(rotate -60 (koch 2)))
(rotate 180 (koch 2))))
Then difine it:
(define (koch-snowflake d)
  (above
   (beside
    (rotate 60 (koch d))
    (rotate -60 (koch d))
 )
   (rotate 180 (koch d))))

For "sprial" ,we need to use substring and string-append to finish it.

We have to understand it and practice more to prepare for the quiz~~@-@

For the third part of wikipedia, I change the grammer and spelling for two articles. It is really hard to find mistakes from wikipedia because it has been changed for a lot of times bu other users.I hope that I can do it well~~