The fixation_dot item is a convenience plug-in. That is, it does nothing which could not be done using a sketchpad item, but is more convenient if you only want to display a central fixation dot.
The following options are available:
Style is default, filled circle, small filled circle, empty circle, small empty circle, cross, or small cross.
Duration should be a positive integer value, 'keypress', or 'mouseclick', to wait respectively for a specified interval in milliseconds, until a key has been pressed, or until a mouse button has been clicked.
Foreground color should be an English color name (e.g., 'blue') or an HTML color value (e.g., #0000FF).
Background color should be an English color name (e.g., 'blue') or an HTML color value (e.g., #0000FF).
The X and Y coordinates reflect the position of the fixation dot.