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 The 20c Martín Güemes shows characteristics of which we do not know yet whether it occurs several times within a sheet or just once.... At least finding it in a few 4-blocks proves that the dot in front of "Martin" is not just an occasional speck of ink :) 
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 Finding a larger block makes it more likely that these characteristics occur only once per sheet: On the first block in the stamp below: 
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 On the second & third block in the stamp above 
 On the second & third block in the stamp left of it: 
 So no repetition in the same column as the 2 characteristics!  |