code: func (w *World) Draw(pix []byte) {
  	for i, v := range w.area {
  		if v {
  			pix[4*i] = 0xff
  			pix[4*i+1] = 0xff
  			pix[4*i+2] = 0xff
  			pix[4*i+3] = 0xff
  		} else {
  			pix[4*i] = 0
  			pix[4*i+1] = 0
  			pix[4*i+2] = 0
  			pix[4*i+3] = 0
  		}
  	}
  }
docs: // Draw paints current game state.