What makes a cat a cat?

When defining a new concept, we need to identify the boundary, i.e. the characteristics (or a specific grouping of characteristics) that make the thing unique.

What makes a cat a cat? Because it is living, which is different from rocks. Because it moves, which is different from plants. Because it catches and feeds on rats, which is different from dogs.

What makes a program different from a program fragment? Because it can compile and run whereas the fragment cannot.

If we find it so hard to identify the boundary of the new concept, chances are that we are trying to invent a new name for a century ancient thing.

It's not what you say, it's how you say it

The instructor did give us an effective two-day presentation: a pretty good course -- made some good points, got us many chances to practice. All of the content sound like common sense, but in fact until someone points those out, you are not aware of them. Even worse, it is so easy to forget and requires so much effort to master when you are on the "stage". I call them commonly insensible common senses.

Just give a boring yet useful list of reminders for myself:
== What ==
- The "So-what". This is a good point, and this is such a common sense: when you speak, think in the position of audience. Why they want to spend half an hour listening your ramble? What benefit can they get from it?
- Get to the main point quicker, get to the "so-what" quicker. "The audience are hopeless impatient." They are so easy to be distracted. So get to what they are really interested in as soon as possible.
- Anecdotal. Examples, not abstract concepts.
- Next step. After the conclusion, you'd better show the audience ways for them to participate, act, or response rather than forgetting what you have said in the first minute.

== How ==
- Take control of your space, be aware of the room. He gave an example that a speaker keeps bumping into a chair. Everybody down there would say "God.. move it!". A confident speaker should observe the room and take full control of his presenting space. You own that space and you should do whatever that makes you comfortable and makes your presentation go smoothly.
- Connection: Eye contact(distribute, keep the connection); use the big screen instead of reading laptop screen; don't talk while not looking at audience
- Be comfortable with pause: It's interesting that it is so easy to learn filling words when you learn another language. I tend to use those filling words right after I hear from someone else, such as "you know", "like" etc. When you are presenting, it sounds really worse than you might think. I started to be aware of this when the instructor echo ed back my filling words. So whenever you are thinking of what to say next, just pause. The audience won't mind that.
- All about variation: volume, pace. The excise really feels like in an acting class. Everyone had to go to the front, and speak out three phases in whatever variation of volume and/or pace to express different emotion.
- Rest position of hands