Welcome to SWI-Prolog (Multi-threaded, 64 bits, Version 7.2.3)
Copyright (c) 1990-2015 University of Amsterdam, VU Amsterdam
SWI-Prolog comes with ABSOLUTELY NO WARRANTY. This is free software,
and you are welcome to redistribute it under certain conditions.
Please visit http://www.swi-prolog.org for details.

For help, use ?- help(Topic). or ?- apropos(Word).

true.

true.

Echo turned on; prompt turned off

Command: cut(x,10,y)
x: No such pipe

Command: weld(x,y)
x: No such pipe

Command: weld(a,x)
x: No such pipe

Command: cut(a,5,b)
b: pipe already exists

Command: cut(a,10,a2)
Cut is too long!

Command: cut(x,10,a2)
x: No such pipe

Command: trim(a,15)
Cut is too long!

Command: weld(a,c)
Can't weld: differing diameters

Command: q
true.


% halt