Indian Poker

Indian Poker (インディアンポーカー) is a type of card which allows one to view the dreams of another. Originally devised by Kuriba Ryouko based on work carried out at Clone Dolly Ideal,  they have been created and spread around Academy City.

Etymology
Indian poker, or, is a poker game where the players see the cards of the other players except their own. Each player is dealt one card which is displayed to the other players, traditionally stuck to the forehead like an Indian feather, followed by betting as to whether they have the highest card based on the other player's cards and their bets.

Appearance
In the manga, Indian Poker cards are depicted as rectangular and light-colored, with a slightly darker hued strip running along the right border and two concentric arches of similar hue in the bottom-left corner.

Most of the card's front is taken up by a box with an image. Many of the seen cards have two flower-like shapes, one in the top-left and one in the bottom-right, over a dark background. Some high-ranked cards have a more shiny image.

The type of dream apparently affects the colors on the card, with orange supposedly being an enjoyable or happy dream.

Production
A dream is recorded on the card by someone who attaches a machine to themselves when they sleep. Then the person who has the card may view the same dream that was recorded on. The instructions for making the machine used to create the card was released by someone online for free. The machine is created by combining various artificial esper power toys. The type of dream input into the card will affect its color, with orange being linked to joy and happiness. To use the card, one must put it on their forehead when they sleep. The aroma elements in the card are smelled while asleep, producing signals in the person's brain and creating the dream. It is also said that the cards are good for learning by having someone of high proficiency in some subject create a card, for example learning another language or becoming skilled in a sport.

Dream Ranker
Those with the ability to create great dreams for others are known as a Dream Ranker (天賦夢路 (ドリームランカー) ). Those that can create useful cards are given ranks, with the highest being "S" or "A" rank, whose cards can sell for lots of money. A similar ranking system is also used for the cards produced.

Transactions
Normally, Indian Poker cards are exchanged between circles of friends without any monetary exchange involved. However, the demand for particular cards increases as the value of the card increases, allowing people to earn an income out of performing transactions involving Indian Poker cards. (One notable exception is the high-ranking Dream Ranker known as BLAU, who distributes his Indian Poker cards for free. ) For this reason, some people act as "traders", who mainly engage in transactions involving Indian Poker cards, notably the exchange of a single card of a particular rank for multiple low-ranked cards or the direct purchase of a card using money.

Background
The original cards which became the basis for Indian Poker were developed as part of the experiments being performed at Clone Dolly's third laboratory, Ideal. Kuriba Ryouko, the creator of Indian Poker, visited Clone Dolly several times prior to its closure. By recording and teaching an impure version of an esper's Personal Reality extracted through their dreams to alter multiple espers' powers in a desired direction, researchers hoped to guide them into creating the "ideal" power they sought, with Yuuri Senya acting as the core. Shundou Toshizou had plans to spread the cards throughout Academy City after the experiment, but they were dashed by the experiment's disastrous outcome and the subsequent shutdown of Ideal after his Board sponsor pulled out (as part of a deal with Shokuhou Misaki).

Long after the Ideal incident, following the conclusion of an experiment where she had been separated into two cyborgs for a year before being recombined, Kuriba Ryouko learnt of her mechanical doppelganger, supposedly another soul created as a side-effect of the experiment which had come to reside in the combined cyborg parts. Unable to come up with a solution to the problem with her own knowledge, she hoped that by distributing the method to create Indian Poker cards and spreading her knowledge through the cards, it would eventually mutate to produce a solution or find someone capable of achieving a breakthrough. Around the same time as Indian Poker was spreading, persons associated with Clone Dolly Ideal, moved to make use of the cards to accomplish Ideal's unachieved goal.

Dream Ranker Arc
Misaka Mikoto is introduced to and given an Indian Poker card by Hokaze Junko in an attempt to apologize for causing her and Shokuhou Misaki to quarrel. She explains it as a popular card used to peek into the dreams of someone. After receiving the card, Saten Ruiko explains its purpose and how it was made to Mikoto. After using the card that night, Mikoto dreams of a world filled with Gekota which greatly pleases her. She frolics around with the Gekota until she is led by one of them to a castle and meets the queen who turns out to be Misaki. She is then forced to be the maid of Misaki for the remainder of the dream. The sheer rage Mikoto felt during the experience allowed her to forcefully leave the dream.

The following day she meets up with the Ringlet curl girl again and is invited to tea. On arriving she finds Misaki also there, displeasing both of them. The two then overhear Aogami Pierce, going by the Dream Ranker name BLAU, distributing erotic dream cards to various other boys for free. After hearing about cards that involve them, Mikoto and Misaki team up to destroy the cards and erase them from the memories of the boys.

Several days later, Mikoto learns from Saten about the ability of Indian Poker cards to help a person in learning a particular skill, which in Saten's case is the skillful use of a kendama toy. Although interested about the effects of Indian Poker cards, she remains apprehensive about using it after her experience with the ringlet curl girl's card. Mikoto then encounters a man who set up a makeshift stand for trading and selling Indian Poker cards. Kinuhata Saiai is also present as the card trader's customer, but Mikoto does not seem to recognize her, and Saiai is off-duty and does not want to engage in unnecessary business. Mikoto keeps her sentiments about Indian Poker cards, until the trader shows his only S-rank card in possession, which he identifies as the Bust Upper.

Jailbreaker Arc
Following the resolution of the problem faced by its creator and with the card supply cut off, Indian Poker started to die off. Saten managed to buy a card for a youth Olympics level running long jump right at the end, and hoped to use the skill in the Jailbreak Trial, but never got the chance to do so.

Trivia

 * This concept is similar to the Level Upper in that it was created and spread throughout Academy City, becoming a trend, in order for its creator to resolve a certain problem they are unable to on their own.