 In considering (un)successful formulas, a natural question arises: can we provide an syntactic characterization of the formulas that are (un)successful? That is, is there a way for us know whether a formula is (un)successful simply by looking at its form? Building off of the work of Visser et al. (1994) and Andréka, Németi, and van Benthem (1998), van Ditmarsch and Kooi (2006) provide one characterization of some of the successful \eqref{PAL+C}-formulas. 