An appearance-modifying device (10; 30), for modifying the visual appearance of a surface covered thereby, comprising: first (11) and second (12) oppositely arranged optically transparent substrates; a spacer structure (13; 32) spacing apart the first (11) and second (12) substrates in such a way that a space between the first (11) and second (12) substrates is divided into a plurality of cells (15, 16; 31a-c). The appearance-modifying device further has, in each cell (15, 16; 31a-c), an optically transparent fluid (19) having a plurality of particles (20) dispersed therein, the particles being moveable in the fluid (19) through application of an electric field; and first (17a, 18a; 33) and second (17b, 18b; 32) electrodes arranged to simultaneously, by application of a voltage across the electrodes, control a distribution of the particles (20) within each of a plurality of the cells (15, 16; 31a-c) from a first, dispersed state in which an appearance of the surface covered by the appearance-modifying device is determined by optical properties of the particles (20), to a second state in which the particles (20) are concentrated adjacent to at least one of the first (17a, 18a; 33) and second (17b, 18b; 32) electrodes in such a way that the appearance-modifying device (10; 30) becomes optically transparent.