The demo is published on this page.
It displays different clocks in different time zones. You can add as many clocks as you want using the plus button. They are arranged on the screen using a circles packer algorithm. You can click on the clocks to change their settings (time zone, caption & design). You can clock on the gear icon to change the global settings (ex: background).
This demo demonstrates how you can reuse existing libraries written in JavaFX in a WebFX application. Here, it is using Enzo, a JavaFX library which implements many controls, and in particular this clock control with 4 different designs. The flip effect when clicking on a clock to display the settings on its back is also taken from this library.
JavaFX has a great feature to implement responsive design in your application (as already described in this previous demo).
For example, this demo layouts the clocks according to the window width & height using a circles packer algorithm, a performance that is not achievable with a standard responsive design approach based on CSS rules.