(Pascal) Метод Start не является статическим для типа Square

program Squares;

uses GraphABC;

type
  Square = class
  private 
    colorSquare: color;
    x, y: integer;
    rotate: boolean;
    health: integer;
  
  public 
    keyLeft, keyRight, keyJump, keyAttack: integer;
    moveLeft, moveRight, Jump, Attack: integer;
    
    stateOfSquare, timeOfJump: integer;
    
    constructor Create(colorSquare: color; x, y, health: integer; rotate: boolean; keyLeft, keyRight, keyJump, keyAttack: integer);
    procedure DrawSquare;
    procedure moveSquare;
    procedure freeFall;
    procedure doJump;
    procedure doAttack;
    
    //метод, группирующий процедуры в объект
    procedure Start;
    begin
      if Jump = 1 then stateOfSquare := 1;
      if timeOfJump = 5 then begin stateOfSquare := 0; timeOfJump := 0; end;
      
      if stateOfSquare = 0 then
        freeFall
      else
      begin
        doJump;
        timeOfJump := timeOfJump + 1;
      end;
      
      moveSquare;
      DrawSquare;
    end;
  end;

//инструкции для создания объекта
constructor Square.Create(colorSquare: color; x, y, health: integer; rotate: boolean; keyLeft, keyRight, keyJump, keyAttack: integer);
begin
  Self.colorSquare := colorSquare;
  Self.x := x; Self.y := y;
  Self.rotate := rotate;
  Self.health := health;
  
  Self.keyLeft := keyLeft; Self.keyRight := keyRight;
  Self.keyJump := keyJump; Self.keyAttack := keyAttack;
end;

//вырисовывание объекта + очки жизней
procedure Square.DrawSquare;
begin
  SetPenWidth(3);
  SetPenColor(colorSquare);
  DrawRectangle(x, y, x + 10, y + 10);
  
  SetFontColor(colorSquare);
  TextOut(x, y - 25, health);
end;

//движение влево и вправо по оси
procedure Square.moveSquare;
begin
  if moveLeft = 1 then x := x - 1;
  if moveRight = 1 then x := x + 1;
end;

//свободное падение
procedure Square.freeFall;
begin
  if y + 10 + 1 < WindowHeight then y := y + 1;
end;

//прыжок
procedure Square.doJump;
begin
  y := y - 1;
end;

//атака
procedure Square.doAttack;
begin
end;

//описание объектов
var
  redSquare: Square := new Square(clRed, 0, WindowHeight - 200, 9, true, vk_A, vk_D, vk_W, vk_ShiftKey);
  blueSquare: Square := new Square(clBlue, 0, WindowHeight - 200, 9, true, vk_Left, vk_Right, vk_Up, vk_LShiftKey);

//нажатие клавиши
procedure KeyDown(Key: integer);
begin
  //событие нажатия клавиш управления redSquare
  if Key = redSquare.keyLeft then redSquare.moveLeft := 1;
  if Key = redSquare.keyRight then redSquare.moveRight := 1;
  if Key = redSquare.keyJump then redSquare.Jump := 1;
  if Key = redSquare.keyAttack then redSquare.Attack := 1;
  //событие нажатия клавиш управления blueSquare
  if Key = blueSquare.keyLeft then blueSquare.moveLeft := 1;
  if Key = blueSquare.keyRight then blueSquare.moveRight := 1;
  if Key = blueSquare.keyJump then blueSquare.Jump := 1;
  if Key = blueSquare.keyAttack then blueSquare.Attack := 1;
end;

//отжатие клавиши
procedure KeyUp(Key: integer);
begin
  //событие отжатия клавиш управления redSquare
  if Key = redSquare.keyLeft then redSquare.moveLeft := 0;
  if Key = redSquare.keyRight then redSquare.moveRight := 0;
  if Key = redSquare.keyJump then redSquare.Jump := 0;
  if Key = redSquare.keyAttack then redSquare.Attack := 0;
  //событие отжатия клавиш управления blueSquare
  if Key = blueSquare.keyLeft then blueSquare.moveLeft := 0;
  if Key = blueSquare.keyRight then blueSquare.moveRight := 0;
  if Key = blueSquare.keyJump then blueSquare.Jump := 0;
  if Key = blueSquare.keyAttack then blueSquare.Attack := 0;
end;

begin
  LockDrawing;
  SetWindowSize(500, 300);
  
  redSquare.x := WindowWidth div 4;
  blueSquare.x := (WindowWidth div 4) * 3;
  
  OnKeyDown := KeyDown;
  OnKeyUp := KeyUp;
  
  while (true) do
  begin
    clearwindow;
    
    Square.Start;
    
    redraw;
  end;
end.