void setup()
{
  size(400,250);
  smooth();
  fill(180,120,120);
}

void draw()
{
  background(255);
  ellipse(random(100,width-100),random(50,height-50),70,50);
  
  // Stopping looping at the end of draw guarantees no repeat
  // unless explicitly called with a 'loop()' elswhere.
  noLoop();
}

// Interaction methods that require the display to update.
void keyPressed()
{
  if (key == ' ')
  {
    loop();
  }  
}

void mouseDragged()
{
  loop();
}

• the first for loop goes x to the right getting you the column, checking only x, exiting when found
  
• the 2nd for loop going y down getting you the row within that column
  

1. void mousePressedStatePlayGame2() {
2.   int x=-1;
3.   int y=-1;
4.   // Begin loop
5.   for (int i = 0; i < cols; i++) { 
6.     if (mouseX > gameBoard[i][1].x-gameBoard[i][1].w/2 &&
7.       mouseX   < gameBoard[i][1].x+gameBoard[i][1].w/2) {
8.       x=i; 
9.       break;
10.     } // if
11.   }
12.   // Begin loop  
13.   for (int i = 0; i < cols; i++) {
14.     if (mouseY >=gameBoard[1][i].y-gameBoard[1][i].h/2 &&
15.       mouseY   <=gameBoard[1][i].y+gameBoard[1][i].h/2) {
16.       y=i;
17.       break;
18.     } // if
19.   }
20.   println(x);
21.   println(y);
22.   if (x!=-1 && y != -1) {
23.     executeMove(x, y);
24.   } // if
25.   else
26.   {
27.     println ("Not found.");
28.   } // else
29. } // func

1.   if((x + 30 >= width) || (x <= 30)){
2.     speed = speed * -1;
3.   } 
   

1.   if (x + 30 >= width) {
2.     speed = abs(speed) * -1; // always negative
   
3.   } 
   
4.   if (x <= 30) {
5.     speed = abs(speed); // always positive
   
6.   }