I love how the color of her hair appears to complement the color of the window she just passed. As others have said, very nice arrangement of color here. Like the shadow casts too!
Shapes and shadows, and as Steve points out, color, really play well in this, along with the odd shape that her leg seems to take with the longish exposure.
Very nice abstract movement surrounded by an interesting array of shapes and the three primary colors. You are especially good at using color in all your photography so it is no surprise you use color well in pinhole photography. I suppose, since varied focus is not an available tool in pinhole photography, wise use of color can help to direct the viewer's eye down the desired path.