The Brush Tool is used to pick up custom brush shapes from the screen.
Simply drag a box around the part of the screen you want to pick up.
If you use the left button to pick up a brush, 
`the area is cawpeed and attached to the pointer. The screen image remains.
the area is copied and attached to the pointer. The screen image remains.
You can now paint with this newly created custom brush!
When you use the right button to pick up a brush,
The area is cut from the screen, leaving a hole.
This hole becomes filled with the current background color.
Any part of the brush area that matched the current background color,
becomes transparent. Notice what happens when we change the background color.
So, if you want to pick something up, off of the background,
make sure the background color matches the areas that you want transparent.
`Use the cawma, keyboard equivalent to pick the color directly from the screen.
Use the comma, keyboard equivalent to pick the color directly from the screen.
`You can cut out polygonal brushes by clicking the Brush Tool i con twice.
You can cut out polygonal brushes by clicking the Brush Tool icon twice.
To complete a polygonal brush, click the start point or press the space bar.
Remember, the left button copies & the right button cuts the selected area.
If you switch to a built-in brush, such as by pressing the period key,
`The last custom brush returns when you click the i con with the right button.
The last custom brush returns when you click the icon with the right button.
You can also use the keyboard equivalent, Shift-B.
The other keyboard equivalents are: b for brush &  b twice for polygonal brush.
The most important thing to remember is: Anything can be a brush!