T employees built a three bay compost bin next to our trial garden. The bin uses wire on three sides and has removeable wooden slats in the front so you can move compost as it decomposes from one bin to the next. It has a removable plastic cover. Because of the removable slats on the front you can harvest finished compost easily. Other versions of this style of bin use wood on all sides.
For pictures of various compost bins, see the Compost Demonstration site of Brooklyn Botanic Garden at