The Physics of Notations (PoN) is a theory for the design of cognitively effective visual notations, emphasizing the need for design grounded in objective and verifiable rationale. Although increasingly applied, no systematic analysis of PoN applications has yet been performed to assess the theory's efficacy in practice. OBJECTIVES: Our primary objective was to assess the scope and verifiability of PoN applications. METHOD: We performed a systematic literature review (SLR) of peer-reviewed PoN applications. We analyzed what visual notations have been evaluated and designed using the PoN, for what reasons, to what degree applications consider requirements of their notation's users, and how verifiable these applications are. RESULTS: Seventy PoN applications were analyzed. We found major differences between applications evaluating existing notations and applications designing new notations. Particularly, in the case of new notations, we found that most applications adopted the PoN with little critical thought towards it, rarely considered its suitability for a particular context, and typically treated and discussed the PoN with few, if any, verifiable details and data. CONCLUSION: The results warrant consideration for those applying the PoN to do so carefully, and show the need for additional means to guide designers in systematically applying the PoN.