Some figures in the book are created using Open3D but their 2D representation on the page is a bit dull and potentially ambiguous.
Those figures are included here in PCD and PLY formats. You can visualize these files locally use meshlab or the VSCode extension 3D Viewer Light.
Hotlinks in the book take you to a web-based online point cloud viewer, based on 3js, that uses a glTF version of the file.