A clock device utilizing a hollow housing having stackable--columnar--first, second and third stations, each having a blinking light emitting diode (LED) controllably connected to a battery through a firm-wired or hardwired circuit with: the upper hour LED being energized first in sequence to present the hour of the predetermined time of day, by flashing such LED in accordance with a control algorithm or first pulse subcode to proved a total number of flashes contained in the time of day, viz., between 1 and 12; a mid-LED being next energized in accordance with a control algorithm or second pulse subcode that is decimally based, i.e., each flash denoting the number of ten minutes blocks or decades contained in the time of day; and a lower-LED being next being energized in accordance with a control algorithm or third pulse subcode that is also decimally based, each flash denoting a number of minute units in a particular 10-minute block, such number being between zero and nine. With such LED's being energized in serial fashion with the hour station providing a traditional hour display and the minute stations providing a decimal based displays, it has been found that children can learn to tell time and to count.

A circuit for producing a numerical signal representative of the value of the physical parameter which is to be displayed and which can assume a given number of values. The signal is applied to a decoder for controlling the display cell. The decoder is so arranged as to render visible a single display element for certain values of the numerical signal and two adjacent elements for other values. The cell therefore comprises a small number of display elements than there are different values to be displayed.

A digital timer with constant resolution comprising a clock and a chain of binary down-counters, each of which corresponds to a timing range which is a mutiple of that of the preceding down-counter. The binary outputs of the down-counters are fed in parallel to display points of a first set of display points, enabling means being provided so that only the output of the most significant down-counter not at zero actuates the display points. A display point of a second set of display points is associated with each down-counter so that only the display point corresponding to the most significant down-counter not at zero is actuated.

Apparatus is disclosed for assistance in learning binary number notation. Various examples of the apparatus are disclosed, each example comprising symbols each of which can be switched between two states in which it is respectively visible and invisible. Further, each symbol is oriented differently to the other symbols or alternatively the apparatus is provided with other insignia which enables each symbol to be distinguished from the others without reference to the others. Similar apparatus with symbols other than visible symbols is suggested.

A novel method or convention of tracking and displaying the passage of time can be implemented in a variety of decorative and interesting timepiece configurations. Three groups of indicators are used. Each group of indicators is distinguishable from the other two groups. Each indicator is capable of displaying one of two states and can be readily switched between the two states. The first group consists of twelve indicators with the number of indicators in one of the two states being indicative of the hour. The second group consists of five indicators with the number of indicators in one of the two states being indicative of the passage of a multiple of ten minutes. The third group consists of nine indicators with the number of indicators in one of the two states being indicative of the passage of a minute. In this manner, the current time is indicated.