Iterative and sequential lifecycles

Hi there, I'm studying IT at college and my lecturer has set the class the following task: "You must describe two iterative and two sequential software lifecycles".

So far, the lessons we've had for our programming unit has consisted of installing a copy of Windows XP in VirtualBox, bypassing activation using a registry modification, installing Borland TurboC and following the lecturer's (extremely rushed) steps to write basic programs – half of the class can't keep up with him. We haven't covered any theory (such as SDLCs), nor has he provided us with any resources for this topic.

I've done some searching on the internet for examples of iterative lifecycles, but I can't seem to find anything other than the iterative model – I need to include 2 in my article.

Searching for sequential lifecycles shows results about the waterfall model, but not much else. Again, I need to include 2 of sequential lifecycles in my article.

I'm not sure if I'm missing something here or not, but I can't seem to find any other examples of SDLCs that match the required criteria set by my lecturer.

Any help would be greatly appreciated.