An optoelectronic display comprises a substrate 32 of semiconducting material and an array of organic light emitting diode pixels arranged on the substrate, which comprises an active circuit for controlling the light emitted from each pixel. A cut recess is formed in the sliding contact surface so as to vertically extend in the surface. A mean of the samples of traditional target azimuth is calculated. A system includes an electronic system including multiple components generating system outputs based on system inputs and the apparatus for identifying a fault in the electronic system discussed above. Also in response to receiving the request from the first participant, an amount of second currency associated with the first participant is incremented.