Hidden away in some otherwise unremarkable corners of the Leiden city hall in the Netherlands are some fairly unknown woodworks by one of the greatest artists to ever grace a high school student’s t-shirt, MC Escher.

The famed artist, known for his mathematically precise artworks that played equally with fractal repetition and surreal, impossible spaces, was introduced to architect H.T. Zwiers in the early 1940s. Zwiers’s latest project was designing the the new Leiden City Hall, and Escher’s work was seen as being particularly appropriate for a public building. Zwiers asked Escher to produce five works to display in the building.

The artist produced two wall panels for the council chamber, a panel for the mayor’s office, a clock face, and some window etchings for the book cabinets in the clerk’s office. The wooden portions were created using a mix of woods and an inlay technique called intarsia. The works maintained Escher’s fascination with fractal patterns, creating repeating cascading designs.

Escher would go on to achieve worldwide acclaim for his designs, which are all but unmistakable today. His original contributions to the city hall building still stand, although they are not as accessible as they once were, given that this is a government building. However, during special civic events such as “open monument days” (the second weekend in September), all the works can still be viewed, save for the glass etchings, which remain off limits.