Difficulties about "Palindrome" (resolved)

I did not understand the part where it has function of "make-palindrome" again.
I was confused about  why would we put another same function in one.
"(define make-palindrome s)
...
(else (string-append
               (substring "Danny" 0 1)
               (make-palindrome (substring "Danny" 1))
               (substring "Danny" 0 1)))"

As I asked one of my friend, he recommended me to set an example and use my note and pen to write all steps out. After doing that, I finnaly got to know that their functions are exercising same way but they mean all diffrent things.

<RESOLVED>

Term Test #2

Dr.Racket part was pretty easy because of work done for project #1.
However, I did not get good marks for the lecture note parts.
I think I should more concentrate on that part in Dec examination.

Finished Project 1

Project 1 was pretty simple.
I can put the functions alone to check the result shown.
This way is a good way to check because (check-expect -) just gives me if it is passed or not.

"
(define (set-up-hand im deg)
  (overlay/align
   "middle" "top"
   (rotate (* -1 deg) im)
   (circle
    (image-height (rotate (* -1 deg) im))
    "solid" (make-color 255 255 255 0))))


(set-up-hand apple 90)"

I finished all my stuffs, but the second-hand rotates counter-clock wise.
As I asked my friend, I became to know I should put negative sign in front of rotate degree to make it clockwise