LETTER 1
I've just received your last letter and am immediately replying. You've asked if I've received your last letter and if I intend to reply. If I may, please let me point out that your having sent your last letter makes the letter you previously sent no longer the most recent, and if I reply, as I am now doing, it is not in response to your second-to-last letter. I cannot, therefore, satisfy the requests you've made in your last letter. I would also observe, by the way, that your last letter does not respond, despite what you affirm (and I quote: "I've just received your last letter and am immediately replying"), to the letter in which I queried, lest I am mistaken (but I am not mistaken, I've got copies), if you had received my last letter and if you intended to reply. Failing any clarification and response from you on these two points, to which I attach (for good reason, I think) particular importance, I shall, much to my regret, be obliged to interrupt our correspondence.
LETTER 2
I have yet to receive your next letter but shall immediately reply. You ask if I've received your last letter and if I intend to reply. You might well wonder how, not yet having received your next letter, I can know that you've asked me if I've received your last letter and if I intend to reply. The answer is simple: all of your letters, and this one will be your three hundred and seventeenth (I have them all, as well as copies of all of mine) begin thus: "Have you received my last letter? If so (and I would be quite surprised if you had not yet (though, should that be the case, do let me know)), do you intend to reply?" That's how you began your very first letter to me. That's how you began your second letter, your third letter, and so on, until your last letter, the three hundred and sixteenth. Reasoning by induction, I've deduced that your next letter will begin like the preceding ones. Consequently, I consider myself authorized to reply to it as if I had already received it. And I reply with the following: I've just received your last letter and am immediately replying. You've asked if I've received your last letter and if I intend to reply. If I may, please let me point out that your having sent your last letter makes the letter you previously sent no longer the most recent and if I reply, as I am now doing, it is not in response to your second to last letter. I cannot, therefore, satisfy the requests you've made in your last letter. I would also observe, by the way, that your last letter does not respond, despite what you affirm (and I quote: "I've just received your last letter and am immediately replying"), to the letter in which I queried, lest I am mistaken (but I am not mistaken, I've got copies), if you had received my last letter and if you intended to reply. Failing any clarification and response from you on these two points, to which I attach (for good reason, I think) particular importance, I shall, much to my regret, be obliged to interrupt our correspondence.

LETTER 3
I've just read your first letter (dated 23 November, 1960. You have therefore written, on average, since that date, one letter every six and two thirds weeks (there never was an interval shorter than six weeks or longer than seven weeks between two of your letters)) and something has struck me. You had written (I remind you, in case you have forgotten): "Have you received my last letter? If so (and I would be quite surprised if you had not yet (though, should that be the case, do let me know)), do you intend to reply?" Besides, I have no trace, in my archives, where I conserve, in a systematic and absolute fashion, all the letters I receive, and the doubles of those I send—I have no trace, I was saying, of any letter from you prior to the one dated 23 November, 1960, the one whose first sentence I've just called to your attention. Nor, for that matter, which is at least as troubling, of that letter from me to you to which you allude in the middle of your letter to me of 23 November, 1960, which bears, in the upper left quarter of the 21x27cm sheet, the format from which you have not deviated in all of these years, in your handwriting, scrawled in pencil, the number 1. Nonetheless, I remember—as one could not more clearly remember—the arrival of your letter of 23 November, 1960. (I had just come home from a working meeting with friends.) The handwriting was strange to me, as was the signature: Q. B. (After forty years, I still know nothing more of your name but its initials.) I immediately replied and our correspondence carries on, forty years later. Since you inform me in that very same letter, the one dated 23 November, 1960, that you conserve in your archives the doubles of all the letters you send and the ones you receive (information you don't neglect to repeat (I realize now as I look over our correspondence) in all, I did say all of your letters) you have certainly kept a double of the one you mention at the beginning of the letter dated 23 November, 1960. You could therefore easily clarify this little mystery.

LETTER 4
I haven't received a thing from you in weeks. What is happening?

LETTER 5 (FRAGMENTS)
I have just received your last letter (finally) and am immediately
replying. You ask if I've received your last letter and if I intend to reply.
...
...
PS - You ask how I will answer your next letter if there is no next letter. You wise ass! Nothing's easier ...
END

Translation: Jean-Jacques Poucel