Money is Becoming Harder to Fake
With the use of micro-optics technology, paper currency is becoming increasingly harder to counterfeit. The technology uses microscopic lenses to create images on the bills that will signal authenticity. Nearly 1 million of these lenses are used to magnify underlying micro-images on each of the newest $100 bills. When you tilt the bank note, Liberty Bells on the ribbon seem to change into the numeral 100. If you tilt the note left and right, the images appear to move up and down. If you tilt the note up and down, the images appear to move left and right. The quick method for validation makes it easier for humans to identify counterfeit bills on the market.
This is an interesting use of a technology, but to me it seemed unnecessary once I learned there is only an estimated $863,100 worth of counterfeit $100 bills in circulation.