M090616a
doughnut-shaped mark with "MADE IN CZECHOSLOVAKIA" in the rim.
Although the central element may differ, all these marks share the same colour, size and font. Two other marks (M180907 and M210906) use a similar doughnut-type design as an addition to the main mark. However, bear in mind that basic similarities in marks often mean nothing. I am merely pointing out an observation.
M090616a
doughnut-shaped mark with "MADE IN CZECHOSLOVAKIA" in the rim.
M090616b
Same as before but with different central element.