Tobias Rehberger in Stuttgart: Who owns the form?

Tobias Rehberger sees the South African artist William Kentridge as a bulbous vase: white, sparsely painted with blue dots and lines and of such a rustic design that it could also be the work of a potter's apprentice.

Kentridge himself takes the form of three branches of a flowering cotton bush, which now protrude from the tall neck of the seemingly clay-like silicone object.

Many such "portraits" have been created over the past three decades: Rehberger interprets a colleague as a vase and then asks him to complete the arrangement by contributing flowers that correspond to his own view of himself.

Forty-four of these ensembles, arranged wall-to-wall in cabinet showcases, form the aesthetically engaging prelude to the retrospective of Rehberger's work at the Kunstmuseum Stuttgart.

Under the title "I do if I don't", director Ulrike Groos set up the largest exhibition to date in his home region.

The people of Frankfurt like to regard the professor, who teaches at the Städelschule, was trained there under Thomas Bayrle and Martin Kippenberger and is very present on the Main, as one of their own.

But he was born in Esslingen in 1966 and his idiom makes it easy to identify as a Swabian.

The show is exceptional not only because of the size of the groups of works, with which Rehberger's most important creative phases from 1993 to the present are illustrated, but also because of the way it is presented, which provides surprising insights into his oeuvre.

The most striking example of this is provided by a series he began in 2004, motivated by his studio windows, which are not shown in front of a wall but in a labyrinth from all perspectives like Renaissance sculptures.

In this way, it becomes clear that behind the abstract compositions made of colored acrylic, MDF or aluminum are actually window frames and their transparency has a function, namely to connect the outside with the inside.

Unlike usual, however, the vases do not stand on pedestals, but are distributed in St. Petersburg style in front of the museum wall like traditional still lifes of flowers on panel paintings.

What connects the "portraits" with the artists, whose names give them the titles, is usually difficult to decipher.

In "William Kentridge", for example, the two-tone vase corresponds to his characteristic charcoal drawings.

However, the crooked vessel has nothing of their virtuosity.

Easier to decipher is the cotton, which suggests itself as a symbol of slave labor and black oppression, which are central to Kentridge's themes.

More important than the interpretation of the form, however, is the question of its author.

Finally, the portraitist and the person portrayed give the portrait a form together.

So is it Rehberger as the idea generator and vase producer?

Is it his colleagues without whose help the objects would be incomplete?

Or is it nature as the creator of plant splendor?

Incidentally, three monstrous termite mounds covered in neon-colored paint, which one encounters in another room, also ask the same question.

In Rehberger's participatory works, on the other hand, the viewer becomes at least a co-author.

It is up to them how intensely a sky full of lamps glows, and they are expressly asked to paint the wall on which abstract sculptures cast concrete shadows.