Uploaded to www.rart.com/Gallery/SampleGallery    May, 2011

Sample Universes

Some sample universes have been around for a long time . However, the newer Java versions demonstrate the Rart™ concept as well as the use of the Rart Development Kit, RDK 3.0. You can here observe and play with selected universes or observe a Continuous Demo


Selected Universes

These universes, except the Demo, are run using the latest rartrunner, RRlet  release, 2.5. RRlet 2.5 was revised to allow the observer to maximize the window and, using a long mouse click, get a pop up menu to among other things modify the parameters.

Note: In this environment the universe, when started in the browser, opens in a new expandable window. When this window is closed, using the close button, you get a browser window with some rests of the observed universe. Hit the browsers back button to get back to where you started your selection to observe the universe.

The Eggs2 Universe


This variation of the older Eggs was added 2010. It changes foreground colors in steps and background color continuously. Normally it goes through a cycle of color changes in an hour, but this can be changed. It also has built in probabilities for other surprises. See the Egg2 universe

The Eggs Universe

This is one of my first universes (originally programmed in QuickBasic for the Macintosh in 1988-89). It demonstrates how very simple shapes interact to form surprising and interesting patterns. See the Eggs universe and make sure to try different color combinations.

The Polygons Universe

This universe is patterned after an early screen saver. While in general screen savers meet the requirements for a Rart universe, randomness etc. the main difference is in the Java environment which encourages the display of the universe over the Internet using almost any Java enabled browser whereas screen savers usually are programmed in code specific to the operating system and computer.. In the Polygons universe the observer can modify the number of corners and the number of lines as well as color. See the Polygons universe.

The Xmas06 Universe

The universe is my first attempt to model some aspect of reality, in this case the snowflake. The symmetric branching of the snowflake is in itself a wonder and causes flakes to be different for simple physical reasons. This universe grows the flakes according to rules which apply until the limit of resolution of the screen is achieved. Originally I programmed the Flakes universein 1998.It was later modified to serve as an animated Christmas card. This version, with suitable and modifiable text went out in 2006. One parameter, "Complexity", influences the nature of the growing flake by shortening the length from a branching point to the next.

The ThreeBalls Universe

Originally this universe was designed to test the incorporating of external files into a Rart universe. In this case three balls in three different colors are provided as GIF-images. As I played around I added bouncing of the balls as well as the ability to show trace of the balls and a parameter for gravity which makes the balls fall down or up. Observe the ThreeBalls universe and try out the trace capability.

The Solar Universe

This universe is closely related to the ThreeBalls universe. I took out the bouncing of colliding balls and added Newtonian gravitation, i.e. each body in the universe attracts (or repels) every other with a force proportional to the product of the masses and inversely proportional to the square of the distance. If anything, this universe shows how difficult it is to end up with a stable planetary system. The parameter "Solar System Configuration" offers a choice of configurations including one with a double sun.



Sample Universes Displayed using rartrunner RRlet, demo version .

The RRlet environment, is programmed to run in browsers that conform to JDK 1.1+. It should be viewable in almost any browser (See the Rart Homepage about how to enable Java for various browsers with Java capability.).

In this continuously running demo you normally get one of several simple universes, text universes with explanatory text displayed for 10-15 seconds. In demo-mode a universe is then selected at random to run from anywhere between 30 and 90 seconds. When a universe is running in demo-mode, a long click initiates a series of dialogs allowing you to change parameters. A long click also adds about five minutes of running time so you can play around some more without being interrupted. On a short click, you get a new selection of universe with new randomly selected parameter values.

In this older version of the rartrunner you can not Maximize the applet window but use a predefined window size. We have provided window sizes 800 x 480 pixels and 1200 x 500 pixels

See Universe Demo with screen size 800-480

See Universe Demo with screen size 1200-500

The applet tag looks as follows for those that are interested

<APPLET ARCHIVE="demo.jar" CODE="rrlet.RRletdemo.class" WIDTH="800" HEIGHT="480" ALIGN="BOTTOM"
alt="( With a java enabled browser you would see animation here)">
<PARAM NAME="UNIVERSE" VALUE="A2">
<PARAM NAME="DEBUG_LEVEL" VALUE="0">
</APPLET>

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