Ludwig Wittgenstein explains the numbering scheme of the propositions of his Tractatus Logico-Philosophicus as follows:
The decimal figures as numbers of the separate propositions indicate the logical importance of the propositions, the emphasis laid upon them in my exposition. The propositions n.1, n.2, n.3, etc., are comments on proposition No. n; the propositions n.m1, n.m2, etc., are comments on the proposition No. n.m; and so on.
This gives the set of propositions of the Tractatus a directed graph structure: namely, there is an edge from P to Q if and only if Q is a comment on P. The connected components of this graph are precisely the seven chapters of the Tractatus. Since each connected component has no cycles, each chapter forms a tree in the graph-theoretical sense.
Thus the Tractatus, graph-theoretically speaking, is a forest of seven trees.
Below you find visualizations of the Tractatus as a whole, as well as each chapter separately. Click on the image to link to an interactive graphic, where hovering over a node produces the corresponding text. As you can see Chapter 7 consists solely of Proposition 7: “What we cannot speak about we must pass over in silence.” (In German: “Wovon man nicht sprechen kann, darüber muss man schweigen.”)
These graphs and their visualizations were made with python-igraph and plotly (for Python). The text for the graphs was taken from the Project Gutenberg eBook of the Tractatus prepared by Matthew Stapleton.