var pages = [
['categories','Categories
select a category'],
['blocks', 'Blocks
drag out a block
double click on it'],
['tools', 'Getting help
click on 
click on something
to exit help'],
['forward', 'forward 100
the turtle moves forward 100 steps'],
['right', 'right 45
the turtle turns 45 degrees'],
['repeat', 'repeat
do something many times'],
['square', '4 x 90 = 360'],
['namedsquare', 'Naming a stack
drag out a 
click on it
type a name'],
['spinsquare', 'Named stacks
use 
to run a named stack'],
['bluesquares', 'set color
on set color to see choices'],
['headingcolor', 'heading
is the direction of the turtle (0 to 360)'],
['headingshade', 'set shade
for lighter or darker colors'],
['boxes', 'Boxes
hold numbers that you can change'],
]