Potassium cyanide," says the talent wrangler as she leans...

Potassium cyanide," says the talent wrangler as she leans over to pick up a paper napkin off the floor. "Found naturally in the cassava or manioc roots native to Africa, used to tint architectural blueprints in the form of the deep-blue pigment known as Prussian blue. Hence the shade 'cyan' blue.