This is a nand gate simulator. Here's some instructions to get started:

• Click on canvas to create a node.
• Press shift and click on canvas to create node with fixed state.
• Drag node over another to create an edge between them.
• Press shift and click on node to destroy it.
• Start dragging node, press shift, move over another to destroy edge between them.

If you're unsure where to start, try out the demonstration patterns shown under the canvas.