Which of these 4 are the "bathtub" formation?

I often hear commentators say a player has a bathtub formation with 4 pawns. The end 2 are on an angle. However, does it matter which direction? It's different from which side you look, one side is concave like a bathtub, and the other is convex, like when putting in a contact lens.

So, personally, I would call the bathtub formation the one from the side making the move when it is concave, and from the opponent's view a contact lens.

Do you agree or do you think bathtub can be used in all 4 formations below?

a3 and d3 are fine. e3, f4 and g4 when played together, significantly weakens your kingside. If your opponent is competent, he will punish this pawn structure weakness, making you lose.

That ain't a bathtub. The one I know like in the CK (game of mine)

lichess.org/editor/2kr3r/pp2qpp1/1np1p2p/4P2P/2P2PP1/4B3/PP2Q3/1K1R3R b - - 0 25

@Sarg0n said in #3:
> That ain't a bathtub. The one I know like in the CK (game of mine)
>
> lichess.org/editor/2kr3r/pp2qpp1/1np1p2p/4P2P/2P2PP1/4B3/PP2Q3/1K1R3R b - - 0 25

Black long castled in Caro-Kann defense? That's quite unusual, when I play Caro-Kann I always castle on the kingside. If I think white will try to castle on the queenside, I wait until he has castled. Then I castle on the same side as him.

@Sarg0n said in #3:
> That ain't a bathtub. The one I know like in the CK (game of mine)
>
> lichess.org/editor/2kr3r/pp2qpp1/1np1p2p/4P2P/2P2PP1/4B3/PP2Q3/1K1R3R b - - 0 25

Your e-h pawns are in the same relative position as the a-d pawns from @HaveToMakeAMove . Just saying "yours ain't a bathtub, here are some pawns in the same relative position and this is a bathtub" isn't very helpful. Why are your pawns in a bathtub position, and the ones from @HaveToMakeAMove not?

@Abigail-III said in #5:
> Your e-h pawns are in the same relative position as the a-d pawns from @HaveToMakeAMove . Just saying "yours ain't a bathtub, here are some pawns in the same relative position and this is a bathtub" isn't very helpful. Why are your pawns in a bathtub position, and the ones from @HaveToMakeAMove not?

Normally you speak of bathtub only when the pawns are fixed.

I mean you cannot play a3 and h3 and having the biggest bathtub in the world.

@SeanRR said in #4:
> Black long castled in Caro-Kann defense? That's quite unusual, when I play Caro-Kann I always castle on the kingside. If I think white will try to castle on the queenside, I wait until he has castled. Then I castle on the same side as him.

Pretty normal stuff.

Bathtub? I always called that The Defirmian Bowl.

More of pear shaped shield!