Complex sentence: The smock mill is a type of windmill that consists of a sloping, horizontally weatherboarded tower, usually with six or eight sides, on top of which is a roof or cap, which can rotate to bring the sails into the wind.
Split into simpler sentences: The smock mill is a type of windmill that consists of a sloping, horizontally weatherboarded tower, usually with six or eight sides. It is topped with a roof or cap that rotates to bring the sails into the wind.