# Overview This section provides an overview of ALFE. We describe its design as well as the capabilities provided by the library. ALFE is organized into different modules. At the core of the library is the FEsystem module providing a data structure for polygonal surface meshes. On top of the FEsystem module the Element module provides implementations of various finite element types such as triangles, pixels, quadrilaterals, tetrahedrons, hexahedrons and voxels. The optional TopOpt module provides topology optimization tools based on Bi-directional Evolutionary Structural Optimization. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://albertlidesign.gitbook.io/alfe/user-guide/overview.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.