[Ur] simple example about constructing rects - guarded types?

[Adam Chlipala]

Adam Chlipala wrote:
> Marc Weber wrote:
>> The demos make use of it multiple times:
>>
>> [...]
>>
>> Or do those ! have a different meaning?
>
> Each of these should be an application of something besides an 
> identifier defined at the top level of a module.

I should also add that I just realized I left around some obsolete demos 
that I haven't tried compiling in probably close to a year.  If you want 
to examine code that will actually compile, I recommend repeating the 
search after pulling the latest version.