@cobra91. The third position is legal, upside down board, which is why all those black pieces are missing, offered up as through-ways for the white pawns. I'll give your boards a good go next week, but I think they might be too much for me tbh
cheers
In the fourth one the easiest way to show move order is to think of white and black squares, as every move by each player had to swap a piece from a black to white square or vice versa
So illegal.
I don't think so
I forgot to say "Black to move".
Not right
@cobra91. The third position is legal, upside down board, which is why all those black pieces are missing, offered up as through-ways for the white pawns.
lol 
That's why I always include board coordinates in my diagrams - otherwise, there'd be at least one person claiming my constructed positions were easily legal, and posting proof games of their 180-degree rotations. However, when others omit board coordinates, I tend to assume they just forgot to include them, and that h1 is intended to be in the lower-right corner. Nobody ever posts flipped diagrams in these kinds of threads, and I've never seen a flipped diagram posted anywhere without specifying the orientation of the board in some way. So your 3rd position was definitely "cruel and unusual". 
So illegal.
I don't think so
I forgot to say "Black to move".
Not right
Like this
In the fourth one the easiest way to show move order is to think of white and black squares, as every move by each player had to swap a piece from a black to white square or vice versa
Yes, the proof is as old as time, so I wasn't going to waste space by spelling the whole thing out.
@cobra91 [...] I'll give your boards a good go next week, but I think they might be too much for me tbh
All but two of the positions I posted have already been proven as illegal, leaving just these:
cobra91: The first one must be illegal. Both white and black need at least 7 pawns to get 2 extra rooks, 2 extra knights and 3 extra light squared bishops. 2+2+3=7. Assuming that 1 pawn walked straight to the other side through a pawnhole on the d- or e-file in the enemy's camp, than the second has to capture one piece to go through that same hole, the third has to capture 2 pieces, etc, which gives 3+2+1+0 (the pawn walking straight through the hole in the opponents camp)+0 (the pawn captured by the opponent to make a hole)+1+2+3=12 captured pieces. The only pieces that could have been captured, at best, are: 1 black-squared bishop, 1 queen and 1 pawn = 3 pieces. I say "at best" which is the case when both parties still have the original 2 knights, 2 rooks and 1 light-squared bishop. Since 12 must have been captured and only 3 could have been captured leaves this position illegal. Ammiright?
The second one ... the second one gives me a headache. Anyway, I like these puzzles. Thanks.
In the fourth one the easiest way to show move order is to think of white and black squares, as every move by each player had to swap a piece from a black to white square or vice versa
Yes, the proof is as old as time, so I wasn't going to waste space by spelling the whole thing out.
@cobra91 [...] I'll give your boards a good go next week, but I think they might be too much for me tbh
All but two of the positions I posted have already been proven as illegal, leaving just these:
it's illegal because the pawns that would promote wouldn't be able to get past each other without capturing each other
illegal
right?
KR6/r7/r7/kR6/8/8/8/8 w - - 0 1
I think its Illegal
legal
I was happy this morning to see that a forum exists already for them (except cobra’s magnificent baroque creations are making my head spin!).
Any analysis to offer for one or two of them?