Yacas is a general purpose, easy to use Computer Algebra System (a CAS is a program that can be used to do symbolic manipulation of mathematical expressions). It is built on top of its own programming language designed for this purpose, in which new algorithms can easily be implemented. In addition, it comes with extensive documentation on the functionality implemented and methods used to implement them.

Rascal, the Advanced Scientific CALculator, is a platform-independent modular calculator. It is based on modules for supporting its various data types, and it can be easily extended with existing C or C++ code. The available modules are integers, long numbers, doubles, strings, vectors, matrices, complex numbers, Taylor arithmetic (automatic differentiation), and fractions.

The Java Penrose Empires Package allows you to compute the empires (forced tiles) for an arbitrary initial patch of tiles. Tilings may be saved for later, and may be exported to PDF, EPS, or PNG. This software represents a new method of computing forced tiles. Rather than using a "growth" approach (where some tiles are randomly forced), this system only shows the forced tiles in the system, leaving all unforced areas blank.

Botan is a crypto library written in C++. It provides a variety of cryptographic algorithms, including common ones such as AES, MD5, SHA, HMAC, RSA, Diffie-Hellman, DSA, and ECDSA, as well as many others that are more obscure or specialized. It also offers SSL/TLS (client and server), X.509v3 certificates and CRLs, and PKCS #10 certificate requests. A message processing system that uses a filter/pipeline metaphor allows for many common cryptographic tasks to be completed with just a few lines of code. Assembly and SIMD optimizations for common CPUs offers speedups for critical algorithms like AES and SHA-1.

MDVI is a library and a previewer for DVI files with the output format of TeX. The previewer runs on the X Window System, but the library can be used in any environment, and supports fonts in PK, VF, GF, Type1 and TrueType formats, and font metric files in TFM, OFM and AFM formats.

gonvert is a conversion utility that allows conversion between many units such as CGS, Ancient, and Imperial. It supports many categories like length, mass, numbers, and more. All converted values are shown immediately as you type. It is easy to add/change your own units. It was written in Python and uses pygtk and libglade.

A practical lambda-calculator is a normal-order evaluator for the untyped lambda-calculus, extended with convenient commands and shortcuts to make programming in it more productive. Shortcuts are distinguished constants that represent terms. Commands define new shortcuts, activate tracing of all reductions, compare terms modulo alpha-conversion, print all defined shortcuts and evaluation flags, etc. Terms to evaluate and commands are entered at a read-eval-print-loop (REPL) "prompt" or "included" from a file by a special command. A Haskell branch is an embedding of the lambda calculator (as a domain-specific language) into Haskell. The calculator can be used interactively within Hugs or GHCi.

This is an application to help user (mathematician) to make regression between series of data, draw grpahics, and export them into various formats by means of common graphics packages (i.e., gnuplot, plotutils). It is written in Python. The user interfeace is built upon the wxPython (wxWindows) widget set. The idea of usage is as follows: the user builds a project which is represented as a tree of modules; modules can generate data variables, as well as consume them. Essentialy, such a tree represents an algorithm of data analysis. The system is intended to educate students.

A collection of fun, creative, elegant, exciting, amusing, useful, and profitable commands.