Z specifications in HTML pages

Z is a formal specification notation used in the field of software engineering. When one wants to include a Z specification on a web page, the most common solution was to use an image. With today's browser, that is no longer necessary. You can use regular (X)HTML markup combined with CSS to display the "boxes" and Unicode for the mathematical symbols. Below are some examples. View the source to see how it's done.

Storage_tank

Storage_tank

Add_OK

Add_OK

Lookup_OK

Lookup_OK