Each level has a hidden card, and the HashRate of the hidden card is twice as much as the HashRate of the card of the same level. The hidden cards are: Moon (level 1), Proxima (level 2), Sensui 4 (level 3), Ursa Major (level 4), Crab Nebula (level 5), Great Spiral Galaxy (level 6), and Singularity (level 7).