Multiple Guess

forms are a mix of slotted holes and 3d objects.  

I note there is no "comments" slot on your 
form for the differently dimensioned, so 
here goes...

There are two lGPL prologs you should consider:
GNU Prolog and SWI prolog.  They have different
attributes and slants.  

SWI makes extensive use of graphical IDE and produces 
executables oriented towards the Windowed 
(Graphical) environment running the development system. 
It's more an all-in-one approach a bit like old Borland 
products.  

Gprolog is oriented towards integration within a GPL
toolchain environment: while is also has a good text
based interp, it links like a standard object using gmake,
Makefiles, etc. and produces code that runs reliably
across the *NIXes, can be run under GDB and interfaces 
to c and system libraries trivially.  

It is a leaner machine and offers full (stable) 
prolog semantics within the *NIX systems environment.  

It also makes a fine desktop calculator.

Dhu


-- 
Ne obliviscaris, vix ea nostro voco.