An optical display element of one embodiment of the invention is disclosed that comprises a binary optical display element and a multiple-bit storage element to store a number of bits of a color intensity value to be displayed by the binary optical display element during a display period. A deviation of the center of gravity of the laundry and a pre-spinning time period are reduced in the aforementioned control method. The filter is able to filter the necessary volume of fluid and in particular blood in an acceptable time frame. The oxygenating bubble supply is operated to provide small bubbles of air or oxygen that intermittently produce aerobic conditions in a significant part of the mixed liquor. The method involves using the ratio of at least one further reagent to principal olefin in the polymer particles in the reaction zone or in the amorphous phase of the polymer particles. First and second clock signals are supplied respectively to the first and second input terminals of the timing averaging circuit, and a clock in which a time difference between pulses of the first and second clock signals is averaged is generated.