The Cross Section of a Toothbrush... was developed from the image of a blue toothbrush with paste that stood in a red cup, on the edge of the sink in our bathroom. This everyday scene was given unique form through Coosje's decision to combine the separate objects into a single shape by clinically cutting through them in two parallel slices. The result was a triangular geometrical form, suggesting a design from the de Stijl movement, yet resembling a sun-dial. As Coosje's perception not only signified her analytical approach to situations but also a union of opposites, Portrait of Coosje's Thinking became part of the title.
In 1983, the Cross Section of a Toothbrush... was installed at a site in Krefeld, Germany, as part of the 100 year anniversary of the Krefelder Kunstmuseum. The sculpture is located in front of the Haus Esters, designed by Mies van der Rohe, an extension of the Museum in the residential area of the city. Because the Haus Esters had originally been a private home the toothbrush seemed an appropriate emblem. Moreover, as a result of Coosje's transformation of the subject, the sculpture is stylistically harmonious with the architecture. The Cross Section of a Toothbrush nevertheless serves as a contrast to the building through its strong diagonal, its vivid color, its changing appearance as one moves around it -- from directly in front it is reduced to a strip -- as well as its lingering pop origin exemplified by the shaved pink paste and brown gum massager against the sky, said to disturb conservative neighbors on the Wilhelmshofallee.