The explorer pane

Logisim organizes tools into libraries. They are displayed as folders in the explorer pane; to access a library's components, you have only to double-click the corresponding folder. Below, I have opened the Gates library and selected the NAND tool from it. You can see that Logisim now stands ready to add NAND gates into the circuit.

If you look through the choices in the Gates library, you'll notice that there was no need for us to develop a XOR circuit earlier: It's built into Logisim.

When you create a project, it automatically includes several libraries:

Logisim allows you to add more libraries, too, using the Load Library submenu of the Project menu. You can see that Logisim has three categories of libraries.

To remove a library, choose Unload Library... from the Project menu. Logisim will prevent you from unloading libraries that contain components used in a circuit, that appear in the toolbar, or that are mapped to a mouse button.

Incidentally, a library technically contains tools, not components. Thus, in the Base library you'll find the Poke Tool (), the Edit Tool (), and other tools that don't correspond directly to individual components. Most libraries, though, contain only tools for adding individual components; all built-in libraries other than the Base library are like this.

Next: The attribute table.