We present a method to fill a container shape with deformable instances of geometric elements selected from a library, creating a 2D artistic composition called an element packing. Each element is represented as a mass-spring system, allowing them to deform to achieve a better fit with their neighbours and the container. We start with an initial random placement of small elements and gradually transform them using repulsion forces that trade off between the evenness of the packing and the deformations of the individual elements. Our method produces compositions in which the negative space between elements is approximately uniform in width, similar to real-world examples created by artists. We validate our approach by performing a quantitative study using spatial statistics.