Fox Trot A is an instance of Mondrian’s "lozenge" paintings, which the artist made by rotating a square canvas forty-five degrees. The artist first experimented with the diamond-shaped format in 1918 as a leading member of de Stijl. Founded in 1917 in Amsterdam, de Stijl was a movement of loosely-affiliated artists cohering around Mondrian and Theo van Doesburg that sought to create a purely abstract art composed of elemental forms and colors. It was also the name of an eponymous journal spearheaded by van Doesburg that published a number of texts central to the movement.

Though minimal in form and consisting only of black and white, Fox Trot A offers a sense of expansion. Because of Mondrian’s strategic composition, the black lines appear to be cropped in a manner that suggests their continuation in space. The painting’s angled upper edges create far more openness than a terminal, horizontal border would allow, seeming to leave the upwards thrust of the parallel vertical lines unconstrained. As such, Fox Trot A exemplifies the manner in which the lozenge freed Mondrian’s work from the stultifying effects of the grid and put painting in dialogue with the supporting wall by defamiliarizing the shape of the canvas. Yet this technique also ruptured the painting’s alignment with the orthogonality of its architectural environment.  Unlike van Doesburg, Mondrian did not think neo-plasticism should be extended to architecture and design.

The painting’s title reflects Mondrian’s deep interest in popular music and dance—new, jazz-inflected art forms that the artist saw as akin to his own formal interest in visual rhythm generated through the "continuous opposition of pure means".