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Earlier versions of the 50,000-rial note (B288a-d) with signatures of Mahmoud Bahmani and Shamseddin Hosseini have solid Farsi text at center front (top), where as later versions (B288e/f) have hatched Farsi text (bottom). The transition from solid to hatched takes place on notes between prefix denominators 10 and 13 (in Farsi).
Courtesy of Sejin Ahn.