Molded articles are provided. An exemplary molded article includes an inner panel portion, a main body portion, and a contoured portion extending between and interconnecting the inner panel portion and the main body portion so as to surround the inner panel portion and be surrounded by the main body portion. The contoured portion includes an outer angular region extending from the main body portion, an inner angular region extending from the inner panel portion, and a vertex region interconnecting the outer angular region and the inner angular region. The outer angular region includes contoured corner segments and contoured intermediate segments extending lengthwise between respective pairs of the contoured corner segments. The contoured intermediate segments have a first maximum thickness. The contoured corner segments have a second maximum thickness. The first maximum thickness is greater than the second maximum thickness. Related methods, assemblies, and apparatus are also provided.