Submitted by Brian H on March 30, 2013
‘Depending on the conditions and how you manage them, you can end up with one type of molecule that is a fullerene-shaped [spherical] that shows as brown,’ said Makatsoris.
‘On the other end of the space there is a donut shaped molecule that appears to be blue. When we were doing the search we were able to switch from the brown to the blue by specifying the colour of the solution.’
Don't know if you could switch on the fly, though.