vane or if it be merely whirled at the end of a string the desired image can be made visible to the fixated eye provided the pulse generator 8 is adjusted to suit the speed of movement and that the image be generated in about 1 10 second or less time so that the integrating effect of the eye 39 s persistance is not lost exact synchronism of rotation and message is not required if the message be brief enough to be grasped by the eye brain in a single exposure which is of course part of the object of the subject invention for example the phrase 34 happy birthday 34 may be loaded into the memory of the preferred embodiment and it is clearly perceptible using saccadic eye movements when the pulse generator operates at about 10 000 pulses per second when the preferred embodiment is suspended from a 25 cm length of string and rotated by hand in the manner of a policeman 39 s billy the phrase 34 happy birthday 34 is perceptible when the pulse generator operates at about 1 000 pulses per second however at this slower pulse rate when the device is stationary saccadic eye movement can only perceive one or two letters of the phrase 34 happy birthday 34 in the preferred embodiment large image sizes and greater brightness can be achieved by using clusters of light emitting diodes for each light source in the array also for greater size and brightness the array may use light emitting electron beam phosphor screen vacuum tubes such as are made by the mitsubishi corporation of japan for use in large outdoor color television displays the electron beam tubes emit red green or blue light from a.