gl‑spikes3d is a small WebGL helper that creates axis‑aligned “spikes” (3‑D arrows) that can be drawn over point‑cloud visualizations built with gl‑axes3d, making it easy to highlight selections or specific points in a 3D scatter plot. It is aimed at developers integrating interactive 3D visualizations—especially scientific or data‑analysis dashboards—who need a lightweight way to annotate individual coordinates within a rendered scene.