(the predecessor) and (the modern version) are 2D physics sandbox applications developed by Algoryx Simulation. They allow you to create interactive scenes where objects behave according to real-world physics laws, including gravity, friction, and fluid dynamics. 1. Getting Started
Installation: Algodoo is now free for PC and Mac. You can also find a mobile version on the Apple App Store.
Built-in Tutorials: The best way to start is the "Crash Course" found in the welcome screen's Tutorial button.
The Sketch Tool: This is the "master tool" that combines drawing, cutting, and adding axles into one gesture-based tool. 2. Core Creation Tools Use the toolbar to create and manipulate objects:
This feature relies heavily on the existing Thyme scripting engine under the hood. The "Smart Connectors" are essentially pre-packaged Thyme scripts with visual wrappers (GUIs). Since Phun/Algodoo already allows on-the-fly property editing, this is a UI evolution rather than an engine rewrite.
The Evolution of Play: From Phun to Algodoo If you’ve ever spent hours building a virtual Rube Goldberg machine only to watch it collapse in a glorious chain reaction, you likely know the work of Emil Ernerfeldt. What started as a Swedish master’s thesis project in 2008 called eventually evolved into
, one of the most beloved 2D physics sandboxes in the world. What is Phun/Algodoo?
At its core, Phun (and now Algodoo) is a digital "sandbox" where physics is the only rule. Using a simple, cartoony interface, users can draw shapes—circles, boxes, and complex polygons—that immediately obey gravity, friction, and buoyancy.
By adding mechanical components like hinges, motors, springs, and thrusters, users can build everything from working internal combustion engines to complex walking robots. The Shift from Phun to Algodoo phun algodoo
Phun gained viral fame on YouTube shortly after its release, but by 2009, it was rebranded as Algodoo by the company Algoryx Simulation AB. This shift wasn't just a name change; it transformed a hobbyist tool into a robust educational platform. Key upgrades included:
The world of (the predecessor to Algodoo) was a digital playground where gravity was a choice and friction was a slider. This story explores the transition from a messy, creative sandbox to a structured world of engineering. The Architect of the Sandbox
Leo didn't play games with levels or high scores. Instead, he lived in a white void where he spent hours meticulously drawing rectangles and circles. To anyone else, it looked like a toddler’s digital coloring book, but to Leo, it was a laboratory.
He was an "Algodoo Architect." He had spent months mastering the hinge tool, the spring tool, and the delicate art of density manipulation. His masterpiece, a massive, multi-stage Rube Goldberg machine, filled the entire canvas. The Moment of Simulation The machine was a chaotic symphony of physics:
The Launch: A massive boulder of "Heavy Metal" sat atop a precarious tower of glass.
The Chain Reaction: When Leo hit the "Play" button, gravity took over. The boulder crushed the glass, which fell onto a see-saw, launching a tiny marble into a series of rotating gears.
The Climax: The marble hit a laser sensor, which triggered a "thruster" attached to a wooden rocket. The rocket soared, only to be dragged back down by a chain attached to a giant balloon.
Every time Leo hit play, something different happened. A slight change in friction on a single ramp would send the marble flying into the void instead of the gears. He spent his nights tweaking the restitution of the surfaces, trying to make the machine "perfect." From Phun to Reality (the predecessor) and (the modern version) are 2D
Years later, Leo stood in a real laboratory, surrounded by steel beams and hydraulic presses. He wasn't drawing on a screen anymore; he was designing a bridge. But when he looked at the blueprints, he didn't just see lines. He saw the "Phun" world. He saw how the weight would shift, how the wind would act as a "force field," and how the friction of the joints would keep the whole thing from collapsing.
He realized that the thousands of hours he spent "playing" in that digital sandbox hadn't been a waste of time. He had learned the language of the universe—one simulated collision at a time.
(formerly known as ) is a 2D physics-based sandbox program created by Emil Ernerfeldt in 2008. It is designed as a "playful" tool that merges science and art, allowing users to build complex machines, explore physics concepts, or simply create chaotic "destruction" scenes in a cartoony, interactive environment. The Evolution from Phun to Algodoo Origins (Phun):
The software began as Ernerfeldt’s master’s thesis project at Umeå University. It gained viral popularity on YouTube for its fluid, intuitive interface. Commercial Transition: In 2008, the project was taken over by Algoryx Simulation AB , a company founded by Ernerfeldt’s former supervisor.
Phun was rebranded as Algodoo in 2009. The change was driven by the difficulty of trademarking "Phun" and the word's association with certain adult websites. Current Status: While it was originally paid software, Algodoo became
for Windows and Mac in 2013. A paid version is available for iPads on the Apple App Store Key Features and Functionality
Algodoo operates on a constructionist learning paradigm—encouraging users to "learn by doing". Drawing Tools:
Users can create boxes, circles, gears, ropes, and complex polygons using a simple brush or knife tool. Physical Elements: The Drag Tool
The engine simulates gravity, friction, restitution (bounciness), springs, hinges, and motors. Advanced Simulation: It includes a dedicated
engine for simulating lasers and lenses, as well as a fluid simulator for creating liquids. Thyme Scripting:
Advanced users can use a built-in scripting language called "Thyme" to automate events or create complex logic within their scenes. Algobox – Sharing scenes - Algodoo
Algodoo is a unique 2D physics sandbox software. It allows you to create, explore, and experiment with physics simulations using simple drawing tools. Originally called "Phun," it was developed by Emil Ernerfeldt and later spun off into a commercial product (though it is now free for personal use).
Whether you are a student learning about gravity, a teacher demonstrating friction, or a hobbyist building complex marble runs, this guide will help you master the basics.
Phun Algodoo – if you mention these two words together to anyone who grew up browsing the internet in the late 2000s or early 2010s, you will likely be met with a nostalgic sigh. For millions of students, hobbyists, and aspiring engineers, Phun and its successor, Algodoo, represented the first time they could play with the laws of physics without needing a degree in mathematics.
But what exactly is the relationship between Phun and Algodoo? Why are they so often linked together in search queries? And why, over a decade later, does this 2D physics sandbox still have a cult following?
This article dives deep into the history, features, and enduring appeal of the software known collectively as phun algodoo.