From MTG Salvation Wiki
- A Rainbow Stairwell deck must be exactly 60 cards, six cards from each of the five colors as well as six artifacts or colorless cards.
- Only one copy of each card in the deck, with the exception of basic lands.
- You must have one each, for each color, of cards with converted mana cost one through six. That is, you much have a staircase of cards starting at one mana and moving up to six, for each color.
- Multicolored cards are not allowed.
An example for the white part of the deck would be: