The subject of the article is the surprising numerosity of parse trees which are obtained by the analysis of Polish statements according to 'Gramatyka formalna jezyka polskiego' (Formal grammar of Polish, GFJP) by Marek Swidzinski. Parser Swigra, implemented by the author, provides a tool to generate GFJP parse forests (i.e. the collections of parse trees for a given sentence). This article presents an improved form of parse forest visualisation which allows to find the sources of sentence ambiguity easily. Swigra is available under the GNU GPL licence, hence anybody is free to use it. The program and some analysis examples are available on the web at URL http://nlp.ipipan.waw.pl/~wolinski/swigra.