In American currency the shape of things to come (not to mention the size and texture) may soon be unfamiliar. Last week, federal District Court Judge James Robertson ruled that the Treasury Department had to find a way to design and distribute currency with features enabling a person without sight to tell the bills apart. Currently, bills in all U.S. denominations are exactly the same size and use the same kind of paper, so there is no tactile way to identify the denomination. The issue is far from settled, and advocacy groups for the vision-impaired are not in agreement on whether to applaud or criticize the ruling, with one group calling the effort "dangerously misguided."

The U.S. Treasury has been introducing a series of redesigned banknotes incrementally since 2004. But the new currency features have more to do with security measures and design than accessiblity to the vision-impaired. Check out the Treasury's interactive notes for an up close look at currency features—there's more on the face of a bill than meets the eye.