http://www.complang.tuwien.ac.at/cti/cgi/cti?texta=:-+nti:nonterminating_goal(turing(t([],%27+%27,[]),s0,[p(s0,%27+%27,s1,%27+%27,r),p(s1,%27+%27,s0,%27+%27,l)],y)).&tna=yes&nti=yes&skipcomp=

http://www.complang.tuwien.ac.at/cti/cgi/cti?texta=:-+nti:nonterminating_goal(turing(t(%5B%5D,%27+%27,%5B%5D),s0,%5Bp(s0,%27+%27,s1,%27+%27,r),p(s1,%27+%27,s0,%27+%27,l)%5D,y)).&tna=yes&nti=yes&skipcomp=