as far as I can see, there are no functions like part3.m or sliding_window.m (except the helper function) in the new starting kit for part 3.
This might have one of the following reasons:
1. Those functions are not provided and we are supposed to implement them from scratch.
2. You simply forgot to add them to the starting kit.
3. I'm kind of blind and just can't find them on the CV web page.
Please tell me which one it is.

greets
chr