In doing this challenge I borrowed heavily from project built in the chapter, but I stored my various rectangles, after converting them to NSValue objects in a mutable array. I then, in the draw method, do a fast enumeration on the array, convert back to the rectangle and then redraw all items each time I add one. Although not terribly efficient, it does show the various ovals on the display. So that part is working. Now I was feeling ambitious and wanted to save the array of objects out.
This is where I am stumbling, I think that what I need to use is encodeArrayOfObjCType:count:at: method but I am not sure of the first and last arguments. I am fairly certain that count: would be the count of items in the array, but I don’t know how to specify the Type or what at: refers to. The more I read in the documentation, the more confused I got. Since the array is not keyed, I am at a loss here.