http://www.mulle-kybernetik.com/artikel/Optimization/pix/class-runtime.png

[class-Foo @ 0x6020]-isa->[metaclass-Foo @ 0x60a0]
[metaclass-Foo @ 0x60a0]-isa->[metaclass-NSObject @ 0xa25f28a0]
[metaclass-NSObject @ 0xa25f28a0]-isa->[metaclass-NSObject @ 0xa25f28a0]
[metaclass-NSObject @ 0xa25f28a0]-super->[class-NSObject @ 0xa25eb060]
[class-NSObject @ 0xa25eb060]-isa->[metaclass-NSObject @ 0xa25f28a0]
[class-NSObject @ 0xa25eb060]-super->NULL
[metaclass-Foo @ 0x60a0]-super->[metaclass-Bar @ 0x60e0]
[metaclass-Bar @ 0x60e0]-isa->[metaclass-NSObject @ 0xa25f28a0]
[metaclass-Bar @ 0x60e0]-super->[metaclass-NSObject @ 0xa25f28a0]
[class-Foo @ 0x6020]-super->[class-Bar @ 0x6060]
[class-Bar @ 0x6060]-isa->[metaclass-Bar @ 0x60e0]
[class-Bar @ 0x6060]-super->[class-NSObject @ 0xa25eb060]