I misspoke/mistyped (whatever the correct verb is) while writing about "The Echo Song" in A Funny Thing Happened on the Way to the Forum. My pal Bob Claster sends the following quote from Mr. Sondheim…
"Echo Song" was cut in New Haven during the tryout because the whole show wasn't working properly and this number (among many others) didn't make enough impact on the audience. It was replaced by "That'll Show Him," which was transferred from Act I to Act II. Burt Shevelove and I decided to resuscitate "Echo Song" for the 1971 revival, where once again it didn't work. It did seem, however, to be more effective than "That'll Show Him" if for no other reason than that it offered some funny staging opportunities.
As I recall the staging from the '71 production, they had Hero up on the balcony of the House of Senex and he was doing a kind of Harold Lloyd number, dangling from it and an overhang — actually more scary than funny — as he sang his part. For what it's worth, I think that song is more appropriate for the storyline but "That'll Show Him" is funnier.