This is from my 2019 calender either the February or the August page.
This stereographic reprojection was generated from a spherical panorama I shot standing near the entry of the Boomerang roller coaster in the Prater amusement park in Vienna, Austria.
![Boomerang Roller Coaster - Stereographic Up](https://www.panotwins.de/wp-content/uploads/2019/01/MMatern_20170602_0395_WienerPraterBoomerang_ReproUp_Web-1024x1024.jpg)
See the interactive version here.