“Two blondes walk into a building. You’d think one of them would have seen it”

“Two men walk into a bar. You’d think the second one would have seen it” is a classic bar joke. A similar joke was posted on the newsgroup rec.humor on October 8, 1997:
 
“Two blondes walk into a building.  You would think that at least one of them would have seen it.”
 
The joke has been frequently credited to Welsh prop comedian Tommy Cooper (1921-1984), but no earlier citations have been found.
   
 
Google Groups: rec.humor
Two Blondes
Bandit
10/8/97
Two blondes walk into a building.  You would think that at least one of them would have seen it.
 
Google Groups: alt.tasteless.jokes
3 blondes walk into…
boomo
11/15/97
3 blondes walk into a building….
youd think one of the dumb cunts wooda seen it
 
Google Groups: alt.humor.puns
high jumper
Patrick W. Sencenich
7/2/02
(...)
2 blonds walk into a building…
You would think that one of them would have seen it…
 
Google Groups: alt.humor.puns
Puns of the Weak 08-23-04
Stan Kegel
8/24/04
(...)
Two blondes walk into a building. You’d think at least one of them would have seen it.  (Tommy Cooper)
 
Twitter
jokesbytweet
@jokesbytweet
Two blondes walk into a building….......you’d think at least one of would have seen it ~Tommy Cooper
11:13 AM - 22 Nov 2007
   
28 June 2008, Birmingham (UK) Post, “No, Joy really isn’t taking the Pisco” by John Wright, pg. 20:
“Two blondes walk into a building. You’d think one of them would have noticed.”
 
Twitter
Jeremy (JerJer)
@n8twj
Replying to @e4VoIP
@e4voip My wife should have been a blond: Two Blonds walk into a building… at least one of them should have seen it.  😊
1:37 PM - 21 Jan 2009
 
Twitter
iPhone Humor
@Humorforiphone
Two blonds walk into a building. You think one of them would have seen it…
4:26 PM - 16 May 2009
     
Google Books
More One Liners, Jokes and Gags
Compiled by Grant Tucker
London, UK: Biteback Publishing
2013
Pg. ?:
Two blondes walk into a building ... you’d think at least one of them would have seen it.
 
Reddit—Jokes
Two blonds walk into a building…
submitted May 24, 2018 by Maddog-ArmchairQB
You’d think one of them would’ve seen it.