Building prototype systems can be one of the best ways to validate assumptions, gain intuition about practical design issues, and provide platforms for future software research. While the research ideas behind these prototypes can be published in top-tier conferences, there are not many venues suitable for focusing on the
actual prototype itself. At the same time, building an FPGA, ASIC, or full-custom computer architecture prototype is a non-trivial endeavor and requires a significant financial and time commitment. This workshop is intended as a forum for the builders in our community to share their practical on-the-ground experiences, to provide a status update on their progress, and to convey insights for those considering prototyping their ideas.