TXYZ: Here's the HTML code for a single tab that meets your requirements:
```html
Tabs
Tab 1
```
Here's how the code works:
1. The HTML creates a single tab element with the class `tab`.
2. The CSS styles the tab to be 80x45 pixels, with a yellowish-green background color, centered alignment, and a cursor pointer.
3. The JavaScript code selects all the tab elements and adds a click event listener to each one.
4. When a tab is clicked, a new tab element is created, added to the DOM, and given the same click event listener.
5. The new tab can then be clicked to create another new tab, and so on.
This way, each new tab has the same functionality as the first tab, allowing you to add more tabs by clicking on any existing tab.