1. The problem involves finding the perimeter of compound shapes made up of smaller rectangles arranged in various "L" or "T" patterns. 2. The perimeter of a compound shape is the total length around the outside of the shape. To find it, we add the lengths of all the outer edges. 3. Important rule: When shapes share sides inside the compound, those shared sides are not counted in the perimeter. 4. To find the perimeter, identify all the outer edges of the compound shape and sum their lengths. 5. For example, if a compound shape consists of rectangles with sides of lengths $a$, $b$, and $c$, arranged so that some sides overlap, the perimeter is the sum of the outer edges only. 6. If you have specific dimensions or a particular shape, list the lengths of all outer edges and add them. 7. Remember to exclude any internal edges where rectangles touch. This method applies to all compound shapes in the grid.