/*Код без проверки, просто заинтересовался как описать свою идею попроще.
Не вышло. Зато я понял что циклы с минимум 3 условиями одновременно - это очень замороченно. 
По идее должен быть более структуированный способ*/

public static void Main (Line [] arrayOfLines)
{
    Line [] linesWithClosing, linesWothoutClosing, currentLinesSet;
    Line line, a,next, previousLine, firstLine;
    
    foreeach line in arrayOfLines{
        currentLinesSet = null;
        previousLine = null;
        firstLine = null;
        
        /*------------------------------------------------
        This block fill only first element in our array
        -------------------------------------------------*/
        a = hasCross (line, null, null, arrayOfLines);
        if (a !=null) 
            {
            currentLinesSet.add (a);
            firstLine=line;
            previousLine = line;    
            }
        else
        {
            arrayOfLines.remove (line)
            //******* EXIT FROM CURRENT ITERATION*****
            continue;
        }
        /*------------------------------------------------
        Now we have frist element in array inititalized variables
        If somebody knows how to refactor this piece of shit
        please help (I mean to many If and Other Cycles) 
        And I have spent 3 bloody hours to organaize this shit in my head
        -------------------------------------------------*/
        next = a; //using "a" from initial check to start CYCLE
        until (next != null)
        {
            next = hasCross (next, previosLine, firstLine, arrayOfLines);
            if (next != null)
            {
                if (next != firstLine)
                {
                    /*ok go with this loop*/
                    currentLinesSet.add (a);
                    previousLine = next;
                    hasCross (next, previosLine, firstLine, arrayOfLines); //Just to find Next Next
                }
                else
                {
                    /*We have found closed lines loop*/
                    next = 0;
                    linesWithClosing.add (currrentSet);
                    break;
                    
                }
            }
        }
    }
    
    Line hasCross{line, firstLineInSet, previousLineInSet, arrayOfLines}
    {
        /* return next Line. NotPrevious! Return Null if no next lines*/
    }
}