Power cube

Power cubes are objects that appear in Amy Rose's version of Hot Shelter in Sonic Adventure and Sonic Adventure DX: Director's Cut. They can be picked up by Amy and be used by the player to open sealed doors or paths by placing them in their matching fixtures, similar to Key Stones.

Description
Power cubes appear exclusively in the version of Hot Shelter that is presented in Amy Rose's storyline. They look like rectangular cuboids made of glass, with two opposing square-shaped sides made of metal, and have each a piece of machinery inside them that can be seen through the glass. The power cubes can be found lying around in specific places in the game's environment, and always appear in sets of four, where each of them are in a different color (purple, yellow, blue and orange).

Power cubes are used to unlock blocked paths and doors found within Hot Shelter. To unlock a path or door with power cubes, the player has to pick up each of the four different colored power cubes present in the area and take them to a nearby fixture with colors that matches that of the respective power cube, and then insert them there. Once all four power cubes are inserted into their respective fixtures, the path or door will be unlocked. If a power cube is inserted into a fixture that does not match it, nothing will happen. However, if inserted or just placed in the proximity of a matching fixture, the power cube will automatically float up and insert itself into the fixture.

Unlike conventional items in the Sonic the Hedgehog series, like Rings, regular keys or Emerald Shards, power cubes do not disappear from the gameplay field and enter the player's in-game inventory once the Amy touches them. Instead, the player has to make Amy manually pick up the power cubes through the game controls, and have Amy carry it by hand during gameplay until they are released. While carrying a power cube, Amy's speed is lowered and her unique actions cannot be performed, such as her Hammer Attack and Hammer Jump.