In the Berlin version the painter is far more removed from the outside world - a chair leg is interposed between his feet and the viewer, and the door to the left of the composition is no longer visible.

The picture has probably progressed to the point where Friedrich laid aside his plein-air drawings of nature and let his own recollection guide the painting to completion.

The reason was that ruler and triangle adhere to the sober simplicity of the studio and to Friedrich's working methods, a number of which involved mathematics.

In 1818 Kersting became the head of the painting department of the porcelain factory in Meissen, but still remained in contact with Friedrich for a time.

Kersting preferred painting portraits with an interior setting, and portrayed people familiar to him in a manner that held personal meanings.

It differs enormously from the "chaotic study" of the painter Gerhard von Kügelgen, which was stuffed with innumerable plaster casts and painting equipment.