Primitive electrochromic displays were also formed by infusing the leaves of the rose with a solution of a PEDOT variant and nanofibres of cellulose via a vacuum infiltration method, while the leaf was still attached to the plant. The mixture was drawn through the pores of the leaf into the compartments of the spongy mesophyll layer. Each cavity acts as an electrochemical cell, and can be treated like an organic pixel. Applying a voltage to the cells causes the colour of the pixels of the leaf to change as the polymer reacts with ions in the leaf.