Recent years have shown rapid development of digital fabrication techniques, making manufacturing individual models reachable for ordinary users. Thus, tools for designing customized objects in a user-friendly way are in high demand. In this paper, we tackle the problem of generating a collage of patterns along a given boundary, aimed at digital fabrication. We represent the packing space by a pipe-like closed shape along the boundary and use ellipses as packing elements for computing an initial layout of the patterns. Then we search for the best matching pattern for each ellipse and construct the initial pattern collage in an automatic manner. To facilitate editing the collage, we provide interactive operations which allow the user to adjust the layout at the coarse level. The patterns are fine-tuned based on a spring-mass system after each interaction step. After this interactive process, the collage result is further optimized to enforce connectivity. Finally, we perform structural analysis on the collage and enhance its stability, so that the result can be fabricated. To demonstrate the effectiveness of our method, we show results fabricated by 3D printing and laser cutting.