Programming assignment 1 of the Stanford University CS193P course
https://cs193p.sites.stanford.edu/sites/g/files/sbiybj16636/files/media/file/assignment_1.pdf
This app is made using SwiftUI framework.
There are 3 themes of cards in the app ( animals, plants, flags ) which you can choose in the lower part of the screen by buttons. Every time you press one of the buttons the random number of cards is shown. Also the order of the cards is random.
There are two sides of each card. One side is filled, another one has a frame and the emoji symbol in the middle. You can flip the card by the tap gesture.