Develop a iPad game

i would like to develop a memory game - where you would have a few icons and place them in a grid - you need to flip and find the matching icons, and this needs to also have a leaderboard functionality, for leader in how quick you've found all the matches. this needs 4 levels of difficulty ( for eg start with 10 , then 20 then 30 etc) this needs to be able to be played on one ipad by one person, but if you put 2 or 4 ipads next to each other it snaps together and your grid enlarges and you can now play as a team.