An object of type “Lines” collects objects of type “Line”. This may be the lines of the original tiling or its dual.
Apart from the usual methods to add and show lines we have the method “eliminateUndefined” to eliminate undefined lines. It uses the procedure “eliminateUndefinedLines”, which lies outside the definition of the class “Lines” because we need it too in the class “Point” to eliminate undefined connections. This is not good style. We would better use the class “Lines” instead of a simple array for these connections. Try it out as an exercise.