Alexander Archipenko did quite a few versions of Flat Torsos. The Met Museum has one in marble, #64.27.4, Bonhams offered a bronze version, Lehmbruck Museum has a green patinated version, and Christies sold a silvered bronze version.

This piece seen in the top view of the Kasser torso is by Georg Kolbe:

Kniender Akt/ Kneeling Nude, c. 1928
George Kolbe, German, 1877-1947
Bronze
Kasser Mochary Collection, "The Figure Examined", at Tucson Museum of Art

I was surprised to learn the following piece, in a vastly different style, is also by Alexander Archipenko:

Rose Torso, c. 1928 Alexander Archipenko (American, b. Ukraine, 1887-1964) Clay, glaze, wood, grout Kasser Mochary Collection, "The Figure Examined", at Tucson Museum of Art

And one more for today, by Maillol:

Eve with the Apple, c. 1899 Aristide Maillol (French, 1861-1944) Bronze, edition of 6 Kasser Mochary Collection, "The Figure Examined", at Tucson Museum of Art Finding the rather small apple!