Utility for testing random and pseudorandom sequences, either as bytes or bit streams, reporting entropy, mean value, serial correlation, chi square, and Monte Carlo estimate of an value, serial co…

Utility for looking up Unicode characters and HTML entities by code, name, block, or description. Written in Perl, compatible with almost any system that runs Perl.

Fourmilab Blockchain Tools provide a variety of utilities for users, experimenters, and researchers working with blockchain-based cryptocurrencies such as Bitcoin and Ethereum. Programs are written…

The Marinchip/Autodesk/Fourmilab floating point benchmark, used since 1980 to evaluate the performance of machines and compilers on trigonometry-intensive floating point computations

Atlast is a FORTH-like threaded language, implemented in standard C, which can either be used stand-alone or embedded in applications to make them programmable and open to extension by users. Float…

Butterfly simulation for the Second Life virtual world in which butterflies track the evolution of a Lorenz system, demonstrating deterministic chaos. All parameters can be set, and avatars can rid…

Double pendulum dynamic system simulation for the Second Life virtual world

Fourmilab Tesseract provides models of a four-dimensional hypercube and three other four-dimensional regular polytopes (the 5-, 16-, and 24-cell) which are projected into the three-dimensional spac…

Solar System Live is an interactive orrery for the Web that lets you view the solar system in a variety of ways for any date between 4713 B.C. and A.D. 8000. An ephemeris can be displayed for any l…

Tracing its heritage to a program I wrote on punch cards for a Univac 1108 in September 1969, FIST generates banners with a clenched fist and block-letter slogan of your choice. Various silly optio…

This repository is the development environment and change log of the Web-based tools that accompany “The Hacker's Diet” book, available for free from Fourmilab. This is a Web application, implement…

Web pages, source code, databases, and resources for Fourmilab's Your Sky Web resource, which produces custom sky maps, horizon views, and virtual telescope images for any location on Earth, date, …

Collection of Web pages and programs in the JavaScript language perform encryption (256 bit secret key AES) entirely within your Web browser—you needn't download nor install any software, and nothi…

Development environment and archive for Fourmilab's Web implementation of the Nuclear Bomb Effects Computer slide rule from the 1962 edition of the book “The Effects of Nuclear Weapons”

C++ program, written using the Literate Programming methodology, which finds anagrams of words or phrases based upon an included dictionary for the crossword game whose name may not be spoken, or a…

Demonstration application developed in 1990 for the AutoCAD Development System (ADS_ which used the ATLAST Forth-like language kernel to implement a true object-oriented database within AutoCAD inc…

Firework launcher (wearable or stand-alone) for the Second Life virtual world

Utility to interconvert ISBN-10 and ISBN-13, re-hyphenate ISBNs according to the standard, and generate Amazon associate links

Fourmilab Web resources

Pumpkin head for Second Life virtual world avatars or static decoration

Astronomical simulations for the Second Life virtual world. Includes a scale model simulation of the solar system, including orbits of asteroids and comets from their orbital elements, simulation o…

Performance benchmarks for the Second Life virtual world, including a scripting facility to automate tests.

This is the code base for the www.ratburger.org site

Second Life wearable attachment which allows querying a variety of information, playing animations and sounds, and access a geometric calculator.

Second Life virtual world avatar built entirely from sphere primitives, inspired by Jim Blinn's “Blobby Man” humanoid mannequin from 1987.

Second Life script package in Linden Scripting Language which implements hierarchical mechanisms including rotation and translation of components and automatic adjustment of child objects. Includes…

Second Life attachment which detects whether the current region is hosted in the cloud and informs the user.

Flying rocket and UFO vehicles for Second Life including autopilot, terrain following, SAM site evasion, and scripting

Realistic simulation of flocking birds for Second Life in Linden Scripting Language

Scripted cube for Second Life for learning and exploring rotation, translation, and co-ordinate systems.