code: func newSymbol(size int, quietZoneSize int) *symbol {
  	var m symbol
  
  	m.module = make([][]bool, size+2*quietZoneSize)
  	m.isUsed = make([][]bool, size+2*quietZoneSize)
  
  	for i := range m.module {
  		m.module[i] = make([]bool, size+2*quietZoneSize)
  		m.isUsed[i] = make([]bool, size+2*quietZoneSize)
  	}
  
  	m.size = size + 2*quietZoneSize
  	m.symbolSize = size
  	m.quietZoneSize = quietZoneSize
  
  	return &m
  }
docs: // newSymbol constructs a symbol of size size*size, with a border of
  // quietZoneSize.