I wrote Alec and Alonzo last week.

I put the letters into envelopes and addressed them, but I didn't seal them up.

That evening something funny happened.
That is, Alec would think it funny, but Alonzo wouldn't be likely to.
I was in a hurry, so I snatched Alec's letter--as I thought--out of the envelope and scribbled down a postscript.

Then I mailed both letters.

I got Alonzo's reply this morning.