problem-set/puzzles/miscell/steamroller.desc created : 07/09/86 revised : 07/07/88 Natural Language Description: Schubert's Steamroller Puzzle Wolves, foxes, birds, caterpillars, and snails are animals, and there are some of each of them. Also, there are some grains, and grains are plants. Every animal either likes to eat all plants or all animals much smaller than itself that like to eat some plants. Caterpillars and snails are much smaller than birds, which are much are much smaller than foxes, which in turn are much smaller than wolves. Wolves do not like to eat foxes or grains, while birds like to eat caterpillars, but not snails. Caterpillars and snails like to eat some plants. Show that there is an animal that likes to eat a grain-eating animal. Versions: steamroller.ver1 : declarative representation created by : W. McCune verified for ITP : 07/09/86 translated for OTTER by : K.R. verified for OTTER : 07/07/88 steamroller.ver2 : A special trick has been used to solve this puzzle. A nested function has been used instead of checking (using predicates) whether, for instance, something is an animal and a fox, animal(fox(x)), has been used, even though this is not within the problem. created by : W. McCune verified for ITP : 07/09/86 translated for OTTER by : K.R. verified for OTTER : 07/07/88