The implemented Photo Sphere Viewer is made by Jérémy Heleine The image bounds of a slide have been set to 4096x2048.
The 2nd panorama is displayed in the Marzipano viewer, see here for the recipe how to make that page and the last panorama is made with the Pannellum viewer.
To see the Street View pictures in Google Maps, click the right ‘Open Street View map’ button below and drag the yellow man to the green circles near the pond in the park.