Electro-optic media and writable display incorporating the same

A method of operating an electro-optic device, wherein the electro-optic device comprises (a) a first surface on a viewing side;

• (b) a second surface on the opposite side of the first surface;
• (c) an electrophoretic medium disposed between a light-transmissive electrically conductive layer and an array of pixel electrodes and comprising a plurality of particles in a fluid, the plurality of particles comprising (1) a first type of particles having a first color, a first charge of a first charge polarity;
• (2) a second type of particles having a second color, a second charge of a second charge polarity;
• and (3) a third type of particles having a third color, a third charge of the second charge polarity;
• wherein the first, second and third colors are different from one another;
• wherein the first charge polarity is opposite to the second charge polarity;
• wherein the plurality of particles are configured to migrate within the fluid in a direction responsive to an applied electric field;
• and wherein the third type of particles are configured to migrate within the fluid in a direction responsive to an applied magnetic field gradient;
• comprising the steps of:
• contacting a first location on a first surface of the device with a stylus comprising a magnetic tip to cause a third type of particles to migrate towards the first location;
• contacting again the first location on the first surface of the device with the stylus comprising a magnetic tip to cause a second type of particles to migrate towards the first location.