continuing  lesson one is Lesson 2 :) Picture 1
lesson 2 is mostly about Objective C , object oriented programing , language syntax , and memory management.

this episode has 8 min intro

then minute 10 to  17-43 is basic oop and cocoa

where they talk about the cocoa framework , in summary Objective C is loos type language with dynamic type id.

afterwared they talked about 2.0 Syntax addition (dot notation synthesis etc’) and naming conventions

43-47 dynamic typing

47-49 nil (null object)

49-50 bool (yes/no instead of true)

50-52 selector - this one is interesting – it’s a way to hold the name or promise of a function as an object , you can check if it exists on an instance invoke in etc’ .

52-53 introspection – objective c name for reflection

53-57 working with oject

57-end overview of the cocoa framework data types.

I’m attaching my assignments as reference.