asked again to place the Illness disk on the PRISM board.

Having placed the Illness disk on the PRISM board, informants were asked why they placed their Illness in the position they chose. In most instances, a succinct explanation was offered, which could be written down or audiotaped.

Some aspects of the initial design of the PRISM task were arbitrary, such as the colours of the Self and Illness disks, and their diameters. The decision to place the Self in the corner of one's life, rather than at its centre, was a purely pragmatic one, to allow the greatest range of distances between Illness and Self. However, some researchers have placed the Self disk at the centre of the PRISM board, or changed the size of the board.

The PRISM+ taskslider barrier is in the safe position and towards the optically reflective surface when the slider barrier is in the armed position; a photodiode for receiving light reflected from the optically reflective surface; a transformer connected to the photodiode; and a capacitor connected to the transformer.
In a preferred embodiment, the slider barrier includes a second notch formed therein, the apparatus further comprising a second mechanical lock removably disposed in the second notch.
Another embodiment of the invention is a safe/arm apparatus comprising a slider barrier having at least one notch formed therein, the slider barrier including first and second optically reflective surfaces; at least one mechanical lock removably disposed in the at least one notch; a linear actuator for moving the slider barrier from a safe position to an