The term 'SAND-FILLED COUNTER' can be described as an hourglass, which is a device consisting of two connected glass bulbs with a narrow neck in between. The hourglass is filled with sand or other granular material, and when the upper bulb is inverted, the material flows through the neck into the lower bulb. The hourglass is used to measure time, and the amount of time measured is determined by the amount of sand in the hourglass.