An eraser-sized, salmon-coloured rock sat on a mossy log, marking the inch.

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Additionally, you can flip the pen over and use it as an eraser, the way you would with a number 2 pencil.

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An eraser icon pops as well, letting you wipe away any mistakes.

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If you have a pencil, you can probably exchange it for an eraser, or maybe a post-it-note or something, if you happen to be sitting at a table with some fourth-graders.

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Once completed, the robot picked up the whiteboard, showed the finished work to the assembled CeBIT hordes, placed it back on the easel again, and then before I could call the Louvre, picked up an eraser, wiped out the drawing, and waiting for his (her?) next subject.

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The permanence of what anyone posts online and the absence of an "eraser" button mean that the embarrassment and potential damage can last forever.

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The chip, which requires no power, works like this: Up to four megabits of data are put into the chip by touching the dot with an encased coil about the width of a pencil eraser.

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