boat

1. wood plus wood. makes 1 long_wood. repeat process. boat require 160 long_wood.
2. long_wood plus long_wood. makes 1 shaft. repeat process. require80 shaft.
3. shaft plus shaft. makes 1 plank. repeat process. require 40 planks.
4. plank plus plank. make 1 _long_plank. repeat process. require 20 long_plank.
5. long_plank plus long_plank. makes 1 very_long_plank. repeat process. require 10 very_long_plank.
6. very_long_plank plus string. makes 1 boat. note! multople t required.