Review:  Passing gains

Functions and related notation
	A function is a component of your program, separate from the rest
		- pure vs. "impure" functions
	Parameters and return value
		- parameters can be any type
		- parameters and naming
		- return ends a function (it is finished)

Blocks again
	Block-structured languages

The Turtle:
	A collection of impure functions
	It can be used to draw a triangle
	How about a spiral?

Writing our own turtle functions:
	Simple one:  Draw a square
		parameters:  Size
	More complicated:  Draw spirals
		parameters:  side count, angle

Turtle spirograph