Variables!

Goals:

Use variables to store values, make code more readable, and to simplify code maintenance.

The statement x=0 creates a variable called x that is assigned the value 0. If x already existed, this statement would update x with the value 0.
The statement x=x+1 would be invalid in math class, but makes perfect sense here. It means: add 1 to the current value of x, then save that result as x.
pause makes the turtle wait the given number of seconds before executing subsequent instructions.
The cs function clears all graphics except the turtle.

Variables are holding tanks for information. These holding tanks are called variables because their content can vary, or change.
In Coffeescript, as in most coding languages, the equal sign does not test for equality. Rather, it assigns the value of the expression on the right to the variable on the left.
The examples below illustrate how variables can be used to simplify code and facilitate code maintenance. Both snippets trace out a five-pointed star. However, the code on the right more clearly shows the logic of our work. Additionally, to draw a star with more points, all you need to do is change one number!

Save all programs for today's class in a folder called Variables. Use variables and loops in each activity.

Code a Polygon program that draws a regular polygon with a random number of sides each time it is run. Use a variable, sides, to save this random value (which must be greater than two!) in memory. The number of times you iterate and calculations for turn angles should be based on sides and not a specific number.
Create a Starburst with random-length spikes, without calling home. In each iteration, save the random value using a variable, so you can use it twice—once to draw the spike, and again to return to the center.
Draw a DonutWithSprinkles. Start by using dots as sprinkles, placing them randomly. For a tougher challenge, make "jimmies", i.e., sprinkles in the shape of little lines that point in all directions.
Draw a HandSpiral that uses random to help determine how far the sprite moves and/or turns. But use a variable in the loop so that the turn radius gets bigger with each iteration.

Create a GrassyField, where the blades can vary a bit, randomly. For an added challenge, draw the blades at slight random angles.