Sometimes Cupquake builds something that is not directly attached to her house. This is the page where said structures are listed.
When Cupquake discovered that her closest Stronghold was located underwater, she built a big, T-shaped platform atop the sea, starting from the Ender Island.
Above water, it is composed entirely of cobblestone, with torches lighting up the area. Underground, due to Cupquake's trouble with building underwater, it is a mish-mash of cobble, dirt, glass and sand.
This structure was built during the Dragon Arch, where Cupquake's main objective was to defeat the Enderdragon, where it played a vital role, as the Stronghold's only entrance. The staircase of the platform ends right atop the Stronghold, only one room away from the end portal.
Due to the defeat of the Enderdragon and consequently the end of the Dragon Arch, this building is out of the focus of the series, as Cupquake doesn't need to go to the End anymore, only occasional trips to harvest enderbees and ender pearls.