Further, the bonding has less restrictions, concerning substrate roughness and planarity than direct bonding. DFS is the basis for many graph-related algorithms, including topological sorts and planarity testing. Other reports suggest that the aromaticity (and planarity) can vary between arsole derivatives. Its large size and planarity have also shown promise as a chromatographic separation material. Efficient planarity testing is fundamental to graph drawing. In one such system deformation from planarity is found similar to that of tetrahelicene. The smaller the value of n the larger the deviation from aromatic planarity. Examples exist where ancillary ligands force the NO donors out of planarity. Planarity of the molecule has proven to be essential for maximum potency. Such complexes are further subdivided according to the planarity or pyramidalization at sulfur. Cyclododecahexaene is non-aromatic due to the lack of planarity of the structure. Cyclobutadiene is the only annulene with considerable antiaromaticity, since planarity is unavoidable.