Being new to processing I know that I have to pay extra attention to the punctuation and the case sensitiviness of the code.
Having done that I persistently get the following error. Found one too many { characters without a } to match it. in the attached piece of code. Honestly I don't know what went wrong and politely ask for some help. Many thanks in advance

// global variables and arrays
int boardWidth = 300; // boardwidth (px)
int boardOffsetX = 200; // horizontal offset of board from desk (0,0)
int boardOffsetY = 100; // horizontal offset of board from desk (0,0)
int boardWrap = 3; // # of cells wrapped around
int cellWidth = 20; // inclusive border (stoke)
int cells = int(boardWidth / cellWidth); // #number of cells/row
int steps = 0; // from play setup
int myStep = 0; // initialisation of steps
String [][]myImage; // image, declaration of the array (2d)

void setup() {
  size(800,600); // desk
  background(255); // color desk (white)
  buttonFillBlack = new myButtons(10, 10, 1, 1, "buttonFillBlack"); // generate buttonFillBlack
}
  /*String myFill = "0"; // default fill of image (white=0, black=1)
  myImage = new String[cells][cells]; // composition of image array
  for (int i = 0; i < cells; i++) { // horizontal loop
    for (int j = 0; j < cells; j++) { // vertical loop
      myImage[i][j] = myFill; // initialisation of image array
    }
  }
  drawBoard(); // goto drawBoard
  //drawButtons(); // goto drawButtons
}

void drawBoardBorder() { // draw the board border
  noFill(); // transparant
  stroke(0); // border black
  rect(boardOffsetX,boardOffsetY,boardWidth,boardWidth); // board border
  for (int i = 0; i < boardWrap * cellWidth; i++) { // transparency loop
  int myTransparency = int(map(i, 0, boardWrap * cellWidth, 255,80)); // transparency values
  fill(255,myTransparency); //set transparency
  noStroke(); // draw 4 decreasing transparent rectangles
  rect(boardOffsetX -boardWrap * cellWidth, i + boardOffsetY - boardWrap * cellWidth,
  boardWidth + boardWrap * 2 * cellWidth, 1); // top rectangle
  rect(boardOffsetX -boardWrap * cellWidth, -i + boardOffsetY + boardWidth + boardWrap * cellWidth,
  boardWidth + boardWrap * 2 * cellWidth, 1); // bottom rectangle
  rect(i + boardOffsetX -boardWrap * cellWidth, boardOffsetY - boardWrap * cellWidth,
  1, boardWidth + boardWrap * 2 * cellWidth); // left rectangle
  rect(-i + boardOffsetX + boardWidth + boardWrap * cellWidth, boardOffsetY - boardWrap * cellWidth,
  1, boardWidth + boardWrap * 2 * cellWidth); // right rectangle
  }
}

void drawBoard() { // draw the board
  stroke(200); // border (stroke 1px) made less invisible
  for (int i = 0 - boardWrap; i < cells + boardWrap; i++) { // horizontal draw loop
    int n = i; // neglect wrap cells for fill check
      if (n < 0) {
        n += cells;
      } else if (n >= cells) {
        n -= cells;
      }   
    for (int j = 0 - boardWrap; j < cells + boardWrap; j++) { // vertical draw loop
      int m = j; // neglect wrap cells for fill check
        if (m < 0) {
          m += cells;
        } else if (m >= cells) {
          m -= cells;
        }     
      if (myImage[n][m].charAt(myStep) == '0') { //check fill value
        fill (255); // fill with white
      } else {
        fill (0); // fill with black
      }
      rect(i * cellWidth + boardOffsetX, j * cellWidth + boardOffsetY, cellWidth, cellWidth); //draw filled cells
    }
  }
  drawBoardBorder(); // goto drawBoardBorder
}


*/
void draw() { }

int buttonUnit = 25; // button draw unit
int buttonBorder = 2; // button strokewidth in px
int buttonFill = 0; // button fill
int buttonFillPressed = #4B5096; // button fill when hovered over or pressed #4B5096  or RGB 75,80,150
myButtons buttonFillBlack; // declare buttonFillBlack


void drawButtons() {
  buttonFillBlack.display(); // draw buttonFillBlack
}


class myButtons { // create class MyButtons
  int x; // horizontal coordinate of button (left)
  int y; // vertical coordinate of button (top)
  int buttonShape; // shape of the button (0= round, 1= square, n= rectangle)
  int buttonUse; // 0= Off, 1= active, 2= hovered, 3= pressed
  String buttonText; // info on the use of the button

myButtons(int tempX, int tempY, int tempButtonShape, int tempButtonUse, String tempButtonText) { // constructor myButtons
  x = tempX;
  y = tempY;
  buttonShape = tempButtonShape;
  buttonUse = tempButtonUse;
  buttonText = tempButtonText;
}
 
void display() {
  smooth();
  strokeJoin(BEVEL);
  stroke(buttonFill);  
  strokeWeight(buttonBorder);
  fill (buttonFill);
  if (buttonUse = O) {       
    int(mytranparency) = 100;
  } else if (buttonUse >= 1) {
    int(mytranparency) = 255;
  } else if (buttonUse >= 2) {
    int(mytranparency) = 255;
    fill (buttonFillPressed);
  }
  if (buttonShape = O) {       
    ellipse(x, y, buttonUnit , buttonUnit);
  } else if (buttonShape >= 1) {
    rect(x, y, buttonUnit * buttonShape, buttonUnit); 
  }
}