Adobe Photoshop/Eraser Tool
Almost everyone knows what an eraser does. It removes a section of a picture. It can be very easy to use if used basically, or very complicated if used to its full potential.
You already have seen how to use the basic eraser. But this tool can do much more then just remove squares.
The mode option sets the eraser to act as a block, a brush, or a pencil. A block acts as a simple square eraser, a brush acts a brush with varying opacity, and a pencil acts as a 1px*1px eraser.
The brush, unlike the other options, requires a little more explanation. Next to "Mode" you will see the "Brush" option. This allows you to set the shape. This is explained further in the Brush lesson.
This sets how much it erases off the picture. at 100%, it removes everything it touches, and at 0% it removes nothing.