Escher created these woodcuts as illustrations for his friend Aad van Stolk’s booklet entitled Flor de Pascua (Flowers of Easter). Although these were made in 1921, when Escher was only 23 years old, they foreshadow future work. ...Sphere, on the second page, is Escher’s first spherical reflection self-portrait. Escher made three more spherical self-portrait prints.... [http://eschersite.com/eschersite/Buy_or_Sell_Original_Escher_Work/Pages/Flor_De_Pascua_Woodcuts.html#11] The next in this series, no. 6, is a self portrait of the artist at work. This is not so much a portrait of Escher as Escher. However, the pattern with the spherical mirror – a silver sphere – was to feature heavily in his later work. This is the first and oldest example of the ‘self-portrait in a spherical mirror’ that was to make Escher world famous years later. Furthermore, in this case Escher may well have perceived the spherical mirror as a star floating around in the universe. After the Second World War, Escher became preoccupied with the theme of stars and planets. This is not entirely surprising. Escher had been stargazing with his father since the age of fifteen, using a telescope that had been bought especially for him in Paris. He included this print in the little booklet Flor de Pascua, created by his friend Aad van Stolk in 1921. The illustrations for this booklet are the first paid prints that Escher made. [https://www.escherinhetpaleis.nl/story-of-escher/self-portraits-1917-1950/?lang=en]