I'm looking to get the "static final int sqdim = 80;" line of code below to decrease by 10, every 10 seconds

1. // Original by Daniel Simionato.
2. static final int winwidth = 1280;
3. static final int winheight = 720;
4. static final int sqpadding = 5;
5. static final int fadevel = 10; //fading velocity
6. static final int randomness = 255;
7. static final int randbase = 16; //base value, to avoid "flashing" squares (squares that change colour too fast)
8. static boolean looping = false;
9. static int lastChange = 0;
10. 
    
11. int sqdim = 80;
12. int numsqrow = (winwidth/sqdim);
13. int numsqcol = (winheight/sqdim);
14. MySquare[][] squares;
15. 
    
16. void initialiseValues() {
17.   sqdim = (int)random(50, 80);
18.   numsqrow = (winwidth/sqdim);
19.   numsqcol = (winheight/sqdim);
20.   squares = new MySquare[numsqrow][numsqcol];
21.   for(int i=0; i<numsqrow; i++){
22.     for(int j=0; j<numsqcol; j++){
23.       squares[i][j] = new MySquare(i*sqdim, j*sqdim, random(randomness)+randbase);
24.     }
25.   }
26. }
27. 
    
28. class MySquare{
29.   final int xpos;
30.   final int ypos;
31.   float randseed;
32.   float updated = 0;
33.   float sred = 0;
34.   float sgreen = 0;
35.   float sblue = 0;
36.   float salpha = 255;
37.   MySquare(int x, int y, float rand){
38.     xpos = x;
39.     ypos = y;
40.     randseed = rand;
41.   }
42.   MySquare(){
43.     xpos = 0;
44.     ypos = 0;
45.     randseed = 0;
46.   }
47.   final void display(){
48.     if(updated-randseed > 0){
49.       sred = random(256) ;
50.       sgreen = random(256);
51.       sblue = random(256);
52.       salpha = random(256);
53.       fill(sred, sgreen, sblue, salpha);
54.       rect(xpos, ypos, sqdim-sqpadding, sqdim-sqpadding);
55.       updated = 0;
56.     }
57.     else{
58.       fill(sred, sgreen, sblue, salpha - (updated+fadevel));
59.       rect(xpos, ypos, sqdim-sqpadding, sqdim-sqpadding);
60.       updated++;
61.     }
62.   }
63. }
64. 
    
65. void setup(){
66.   size(winwidth, winheight, P2D); 
67.   initialiseValues();
68.   noSmooth();
69.   background(0.0f, 0.0f, 0.0f);
70.   PFont font = createFont("Courier New", 12);      // acd - changed this
    
71.   textFont(font);
72.   textMode(SCREEN);
73.   fill(128.0f, 128.0f, 128.0f, 256);
74.   String str = "C L I C K   T O \nS T A R T / P A U S E" ;
75.   text(str, winwidth/8, winheight/2);
76.   noStroke();
77.   noLoop();
78. }
79. 
    
80. void draw(){
81.   if (millis() - lastChange > 10000) {
82.     initialiseValues();
83.     lastChange = millis();
84.   }
85.   if(looping){
86.     background(0.0f, 0.0f, 0.0f);
87.     for(int i=0; i<numsqrow; i++){
88.       for(int j=0; j<numsqcol; j++){
89.         squares[i][j].display();
90.       }
91.     }
92.   }
93. }
94. void mousePressed(){
95.   if(!looping){
96.     loop();
97.     looping = true;
98.   }
99.   else{
100.     noLoop();
101.     looping = false;
102.   }     
103. }