//note: we declare the class \samp{A}, without attributes,
class A {
}

//note: we declare the class \samp{B}, which inherits from \samp{A},
class B : A {
}

//note: we declare the class \samp{C} that encapsulates an array of \samp{B} instances,
class C {
	B[] b
}

//note: we declare the class \samp{D} that encapsulates an association to an instance of
//note: class \samp{A} and an array of \samp{C} instances,
class D {
	A a
	C[] c
}