Demonstrates building a particular variant of a 2,3,4 Tree (B-Tree of order 4). This AV is specific to 2,3,4 Trees and shouldn’t beviewed as a "typical" instance of how B-trees work in general. In particular, the rules for pre-splitting internal nodes on the way down during an insertion are specific to the 2,3,4 Tree.The applet launches multiple windows. The Explanation window gives a brief description of the algorithm. The Algorithm window shows pseudocode, with the novel ability to expand the level of detail. The AIA window shows the animation. The Help window shows hints about use of controls that the mouse is currently over.Clicking parts of the program code will show an explanation in natural language within the Explanation window.

Sophisticated use of pseudocode that can expand to show more detail. An "Explanation window" describes how the tree works. The AV does not support the ‘delete’ op; it supports everything else well. As an extra bonus, you can pop open another window that shows the corresponding Red Black Tree (without pseudocode or explanation).

The link takes you to the AIA front page, where you click the "enter" button to reach the index page. From there, click on the link to the desired AV, and it will load as a multi-paned Java applet. Note that the level of detail shown in the visualization is directly tied to the level of detail that you choose to expose in the pseudocode pane.