Introduction

Twenty One is a card game inspired by Solitaire and Blackjack. The purpose is to create series of cards totaling 21 and cumulate the highest number of points in a given time limit

Note: to return to the game at any time, press the BACK key of your device.

Playing the game

A card is drawn from a virtual deck and shown in the screen bottom area. You can drag and drop it into any column of the board. Once a card is dropped into a column, the following rules apply:

1. If the selected column is free, the card is placed on top of that column, then, a new card is drawn from the virtual deck and made available to you for playing it

2. If the selected column contains at least one card, the dropped card will be stacked above the existing cards, provided this will not result in a pile of cards exceeding 21

3. If the card cannot fit in your selected column, it will be rolled back to its initial position ready to be dragged and dropped again somewhere else

4. Upon dropping a card, if you compose a two to four cards pile totaling 21, the pile will be cleared, and the associated column will become entirely free again

5. Upon dropping a card, if you compose a five cards pile totaling 21 or less, the pile will be cleared, and the associated column will become entirely free again

6. Whenever a pile of cards is cleared, the cleared cards are kept aside and not reshuffled with the virtual deck. A reshuffling of all cards, except for those still present on the board, takes place when the virtual deck is exhausted

7. The game is over when there is no longer an available column to drop a card into it.

Scoring policy

The game comprises 52 cards consisting of the Ace, 2, 3, 4, 5, 6, 7, 8, 9, 10, J, Q and K cards in four categories known as Clubs ♣, Diamonds ♦, Spades ♠ and Hearts ♥ where each card has an associated value:

1. All cards numbered from 2 to 10 have a value equal to their numbering irrespective of their categories

2. Jack, Queen and King cards have a value equal to 10 irrespective of their categories

3. Ace cards have a value equal to 1 if they are combined with two or more cards irrespective of their categories

4. Ace cards have a value equal to 11 if they are combined with only one card having a value of 10 irrespective of the category

Whenever you build a pile within any column on the board, if, the total value of the stack reaches 21 you have made a “Twenty One” and the pile is cleared. Note that there is an exception with piles of 5 cards, where such piles will clear if their value is less or equal to 21. The score points are computed as following:

1. Ace card with any card having a value of 10: 51 points

2. Three cards totaling a value of 21: 31 points

3. Four cards totaling a value of 21: 21 points

4. Five cards totaling a value less or equal to 21: Value of the pile

About the user interface and navigation

The user interface was meant to be minimalistic and besides the gesture to drag and drop cards, it uses the following keys:

1. Device’s BACK key

2. Application on-screen HELP key

3. Application on-screen NEW key

Pressing the BACK key has the following effects:

1. If the game is running, a dialog box prompts you whether you decide to exit the application or not

2. If the game is over, the game will exit instantly without prompting you. Note that whenever you exit a game that was over, a new one will be automatically started when you re-open the application

3. If an OK single button dialog box is currently shown on the screen, this dialog box will be discarded

4. If you are browsing the help file, you will resume the game

Pressing the HELP key opens the help file, and pressing the NEW key starts a new game but will prompt you if a current game is running as indicated by a running countdown timer. The top bar displays the following information:

1. Current game score preceded by the keyword SCORE

2. Number of cards remaining in the deck preceded by the keyword DECK and this information is only shown in portrait mode

3. Remaining time preceded by the keyword TIME

4. Last recorded high score preceded by the keyword TOP and this information is only shown in portrait mode

Tips and hints

There are no specific success rules for this game given that the cards drawing sequence unfolds at random, where, you have to perform your best for distributing them in a fashion to easily compose piles of 21. Obviously, the most difficult cards to deal with are those having a value of 10, because, they fill up the pile value quickly making it more difficult to accommodate other cards. The following tips might help:

1. Spread if possible, in different columns, cards having a value of 10, especially if they tend to appear one after the other. Remember that if you ever compose a two cards pile of 10 + 10, you will have to wait till an Ace card appears for clearing it! In the mean time, you might end up loosing the game due to non-availability of free columns!

2. Remember the notable two cards combinations 9 + 2, 8 + 3, 4 + 7 and 5 + 6 that are useful to handle any card having a value of 10. Build in advance such piles, to prepare for such eventualities

3. Consider also combinations like 6 + 6 + 9, 6 + 7 + 8, 7 + 7 + 7 or 9 + 8 + 4 that have a certain statistical recurrence

4. Consider the Ace cards mostly to clear mostly the dreaded 10 + 10 piles!

About Twenty One