text: #include <stdio.h>
  #include <string.h>
  #include <stdint.h>
  #include <stdlib.h>
  #include <time.h>
  #include <assert.h>
  #include <stdbool.h>
  #include "sds.h"
  #include "SDL2/SDL.h"
  #include "SDL2/SDL_ttf.h"
  #include "SDL2_gfxPrimitives.h"
  
  #ifndef _GLOBAL_CONSTANTS
  #define _GLOBAL_CONSTANTS
  
  #define WINDOW_TITLE "tetris-sdl-c"
  
  // a block 'pixel' of a playing field is 15px by 15px in size
  #define BLOCK_SIZE 20
  
  // standard size of a tetris playing field
  #define PLAYFIELD_HEIGHT 22
  #define PLAYFIELD_WIDTH 10
  
  #define WINDOW_HEIGHT PLAYFIELD_HEIGHT * (BLOCK_SIZE + 1) + 1
  #define WINDOW_WIDTH PLAYFIELD_WIDTH * (BLOCK_SIZE + 1) + 1
  
  #endif
  