There is a MagicConference and all kinds of characters can participate by purchasing SinglePass or GroupPass.

The composite pattern is used to create hierarchical, recursive tree structures of related objects where any element of the structure may be accessed and utilized in a standard manner.  From

protocol Pass:CustomStringConvertible{
    var name: String { get }
    var price: Int { get }
    var countNumber: Int { get }
}

struct SinglePass: Pass {
    let name: String
    let price: Int
    var countNumber: Int { return 1 }
    var description: String { return "\(name) (Single Pass \(price)#)" }
}
struct GroupPass: Pass {
    let name: String
    var passes:[Pass]
    var countNumber: Int {
        return passes.map{$0.countNumber}.reduce(0, combine: +)
    }
    var description: String {
        var str = "\(name) (Group Pass \(price)#)"
        str += passes.map{$0.name}.reduce("", combine: {$0 + "\n" + $1})
        return str + "\n"
    }
    var price: Int {
        return passes.map{$0.price}.reduce(0, combine: +)
    }
    mutating func addPass(pass: Pass){
        passes.append(pass)
    }
}

//: The ConfHost oversees the conference, including total passes, total number of participants, costs, etc.
class ConfHost{
    private var passes: [Pass] = []
    init(passes: Pass...){
        self.passes = passes
    }
    func printParticipantList(){
        passes.map{print($0.description)}
    }
    var totalPrice: Int {
        return passes.map{$0.price}.reduce(0, combine: +)
    }
    var totalNumberOfParticipants: Int {
        return passes.map{$0.countNumber}.reduce(0, combine: +)
    }
    
    func getConfOverview(){
        print("MagicConf has sold \(passes.count) passes for \(totalNumberOfParticipants) participants")
        printParticipantList()
        print("Total Revenue: \(totalPrice)#")
    }
    
}

//: Just a helper extension
extension Int {
    func times(action: (Int)->()) {
        for i in 0..<self {
            action(i)
        }
    }
}
//: Adding 7 dwarfs
var dwarfGroup = GroupPass(name: "Dwarf Group", passes: [])
7.times { dwarfGroup.addPass(SinglePass(name: "Dwarf # \($0)", price: 10))}

let singleP1 = SinglePass(name: "Cinderela", price: 12)
let singleP2 = SinglePass(name: "SnowWhite", price: 10)
let singleP3 = SinglePass(name: "The Wicked Witch", price: 10)

let groupP1 = GroupPass(name: "Beauty Group", passes: [singleP1, singleP2])

let confHost = ConfHost(passes: groupP1, singleP3, dwarfGroup)
confHost.getConfOverview()

composite