Write this code::

    theList = [2, 3, 5, 7]
    x = 5

    i = 0
    while i < len(theList):
        if theList[i] == x:
            print "yes"
            break
        i = i + 1

    lo = 0
    hi = len(theList)
    while lo < hi:
        mid = (lo + hi)/2
        if theList[mid] == x:
            print "yes"
            break
        if theList[mid] < x:
            lo = mid + 1
        else:
            hi = mid

on the black board, pretending that we're just explaining the
algorithms.  Then reveal that it's python and show code.py and run it.

Make them functions, run them.

Interactive play -- copy and paste linear_search and binary_search and
play around with them, and lists, and dicts, and tuples.

Attributes -- starting with f.func_name, dir(), ...

Methods -- list.append(), list.sort(), the string type and its
methods.

Strong typing (123 != "123") and more words like "Dynamic typing like
prolog and not like Java".

for loops and range.

files.

example freq.py -- counting the letter 'e' in text files

trivial class Rectangle, with getarea, then add __init__.

then redo freq.py using classes.