Quadrapassel: wrong distribution?

[Blue Glacier <blueglacier414 gmail com>]

Hello,

I have a feeling that there must be something wrong with the 
distribution of the pieces in Quadrapassel. Almost every game starts 
with a dozen of "S"-pieces, but "I" and "J" appear very rarely in the 
entire game. This is strange.

Is this unequal distribution deliberate or shoult it be rectangular?

Quadrapassel version 3.8.2
on Debian GNU/Linux

Greetings,

Blue Glacier

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