Stronghold the Moving Fortress (SD10-EN031) [Structure Deck: Machine Re-Volt]

After activation, Special Summon this card in Defense Position; it is treated as an Effect Monster Card (Machine-Type/EARTH/Level 4/ATK 0/DEF 2000). (This card is still treated as a Trap Card.) While Green Gadget, Red Gadget, and Yellow Gadget are all face-up on your side of the field, the ATK of this card becomes 3000.