The clock is read from the top row to the bottom.
The top row of four red fields denote five full hours each, alongside the second row, also of four red fields, which denote one full hour each, displaying the hour value in 24-hour format.
The third row consists of eleven yellow-and-red fields, which denote five full minutes each (the red ones also denoting 15, 30 and 45 minutes past), and the bottom row has another four yellow fields, which mark one full minute each.
The round yellow light on top blinks to denote even- (when lit) or odd-numbered (when unlit) seconds.