To present some Conditional Formatting in the DDD solution, another little bit of Math is employed. I prefer to use Conditional Formatting to give visual feedback during the design to let me know if I have exceeded design limits. But not to retrict me at the same time.
There is another (simpler) method, which will prevent or limit expressions from returning values outside of a specified range, shown in the video too.
This first video shows the theory behind Conditional Formatting, the next will demonstrate how to set it up with Graphics in a design file.