Apps to Infinite hierarchical depth

ThinkComposer is a highly flexible visual modeling tool designed for users to create rich, structured diagrams based on their specific domain knowledge. It facilitates the organization and visualization of complex information through various diagram types and hierarchical structures, enabling deep understanding and effective communication of ideas.

Gruik is a powerful, free, and open-source note-taking service designed for users who value privacy, organization, and control over their data. Offering robust features like hierarchical organization, offline access, rich text formatting, and synchronization options, it provides a flexible platform for managing notes, ideas, and personal knowledge wikis.

MyTetra is a versatile, cross-platform information manager designed for collecting, organizing, and managing various types of data. It excels as a portable note-taking application, personal information manager, and notebook, offering a robust outliner and rich text editing capabilities.

Org-mode is a powerful and flexible mode for GNU Emacs, designed for note-taking, project planning, to-do list management, and authoring documents. It utilizes simple plain text files with intuitive markup.

KeepNote is a versatile note-taking application designed for organizing information in a hierarchical structure. Available on Windows, Linux, and macOS X, it features robust organization tools, including a tree-like outline, wiki-like linking, and support for embedded files and images. Although discontinued, its local storage and rich features make it a compelling tool for detailed note-taking and research.

OpenNote is a free and open-source web-based note-taking application designed as an alternative to commercial offerings like OneNote and Evernote. It focuses on providing a lightweight yet feature-rich environment for organizing your thoughts and information.

wikidPad is a free and open-source wiki-like notebook application that allows you to store your thoughts, notes, and snippets of information in a highly organized and cross-referenced manner. Its strength lies in the effortless creation of links between pages, making it easy to navigate and connect related ideas.

Leanote is a versatile self-hosted note-taking application that blends rich text editing with Markdown support. It offers seamless synchronization across multiple devices and features built-in blog publishing capabilities, making it a powerful tool for both personal information management and content creation.