Figure 3-7 Mistake-Proofing the Design of Health Care Processes - Figures 3.7A-B. Polarized plugs fit into polarized outlets only one wayA. Polarized plug B. Polarized plug warning labelReturn to Document Current as of May 2007 Internet Citation: Figure 3-7: Mistake-Proofing the Design of Health Care Processes -. May 2007. Agency for Healthcare Research and Quality, Rockville, MD. http://www.ahrq.gov/professionals/quality-patient-safety/patient-safety-resources/resources/mistakeproof/mistakefig3-7.html