The Deo Gracias Fresco in the Heiligen Geist Kirche (1326) in Wismar is a fresco on lime plaster that depicts a combinatorial puzzle made up of 99 letters. The Latin phrase (in the Medieval Latin spelling instead of ; means "thanks be to God") can be read in 504 ways. In a hospital church, the riddle can be understood both as a praise to God and as a remedy. The representation of praise as a puzzle and a learning aid for abstract thinking is unusual and therefore valuable.
No other frescoes of this kind have been found in Germany.
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