.
As explained in previous posts, I have 
a systematic procedure for generating extreme B T&E(1) puzzles from minimal T&E(3) ones, or from their min-expands. As previously, I consider "extreme B" to mean "B ≥ 12" (justified by the unbiased B distribution).
Reminder: the procedure is very simple (but time consuming in the "compute minimals" part): take the 1-expands of the T&E(3) min-expands, filter those in T&E(1) and with B ≥ 12, compute the minimals of the latter and filter those in T&E(1) (which are guaranteed to have B ≥ 12). Notice  that, for each puzzle in T&E(3), the whole process remains within the same solution grid (in particular, there's no {-p +q} search.
As mentioned in previous posts,  
the mean throughput is 1.28  B12+ puzzle for each T&E(3) min-expand. As far as I know, this is the first time some kind of extreme puzzle can be obtained from another kind in a systematic way. What's also noticeable is, no similar procedure works to obtain high BxB puzzles in T&E(2).
I've just published on my Google drive a zipped collection of 504,481 such puzzles with their B ratings (corresponding to only a part of mith's T&E(3) collection):
https://drive.google.com/file/d/1wSkSokvR8maE9yQJI3_X1NSb5ank35IU/view?usp=share_linkThe distribution of B ratings in %  (in the [12 24] interval is as follows:
- Code: Select all
- 12      13      14      15     16     17     18     19     20      21      22       23        24
 45.02   25.81   14.09   8.88   3.70   1.54   0.62   0.23   0.091   0.018   0.0040   0.00079   0.00040
For the most extreme values, this means
- Code: Select all
- 3126 B18 puzzles
 1141 B19 puzzles
 461  B20 puzzles
 92   B21 puzzles
 25   B22 puzzles
 4    B23 puzzles
 2    B24 puzzles
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