And now the samples,

maybe we could see easier graphically

Distribution of the first sample "x"

BIG plate 24x16 cells.

   A  B   C  D  E   ...  M   N  O   P
1 x1  .  x2  . x3   ... x7   .  x8  .    
2 ---------------------------------------- # row of separation
3 x9  .  x10 . x11  ... x15  .  x16 .
4 ----------------------------------------
5 x17 .  x18 .           ...etc
6 ----------------------------------------
...
24
[download]

Distribution of the second sample "y": first you fill the spaces between the first sample, ok

   A  B   C  D  E  F    ...   N  O   P
1  . y1  .  y2  . y3    ...  y7   .  y8      
2 ---------------------------------------- # row of separation
3  . 
4 ---------------------------------------- # row of separation
5  y9
24
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and then, all seems too random and confusing to me, y9 should be in B2, but you say this is in A5. Can you explain better this? (Forget the complicated names, call the samples simply: first, second, third and fourth or w,x,y and z if you prefer)