;; Problem Set 4:


;         ---- FIRST STUDENT ----
;
;
; Name (first, last):
;
; Victor Chern
;
; UBC Student ID number: 32797110
;
; CS Department account ID: o8m8
;
; Lab section: L1W
;
; Lecture section (circle):
;
; 101 (Gregor), 102/BCS (Joanna), 103 (Ron)
;          ---- SECOND STUDENT ----
;
;
; Name (first, last):
;
; Yoo La (Olivia) Sung
;
; UBC Student ID number: 29725116
;
; CS Department account ID: t5p8
;
; Lab section: L1W
;
; Lecture section (circle):
;
; 101 (Gregor), 102/BCS (Joanna), 103 (Ron)


(require 2htdp/image)
(require 2htdp/universe)

;; =================
;; Constants:

(define WIDTH 800)
(define HEIGHT 600)

(define SPEED 1)

(define TEXT-SIZE 12)
(define TEXT-COLOUR "pink")

(define MTS (empty-scene WIDTH HEIGHT))

;; =================
;; Data Definitions:

(define-struct number (x y))
;; Number is (make-drop Integer Integer)
;; interp. A number on the screen with x and y co-ordinates
(define