public String extractSequence (int len)	{
		StringBuilder sb=new StringBuilder();
		int a,pos=counter-len;
		if (pos<0) pos=totalLength-pos;
		for (a=0;a<len;a++)	{
			if (this.get(pos)==true) sb.append("1");
			else sb.append("0");
			pos++;
			if (pos>=totalLength) pos=0;
		}
		return sb.toString();
	}