I think they tried to copy Concorde and then stuck extra bits on until it would fly. 
Actually, it pipped Concorde to the post. It first flew before Concorde, and first flew supersonic before Concorde.
Turned out to be a bit crashy, though. https://www.youtube.com/watch?v=gWIWAI6GmQQ
I believe NASA were flying one not too long ago. Not sure if they still have it even. 
Seem to remember the Russian copy was Code Named Concordski and it keep crashing in test flights, seem to remember the flown one had small wings flaps just behind the cockpit to keep it stable.
wasnt the Pan Am one scrapped before it was tested and called something like the SS1 or SSP or something, all from memory going back to the late 60's early 70's. 
Yes Zirk, there was an American SST that reached the full design stage, with, if I remember correctly, at the time at least one mock up in Pan Am livery, and artist impressions of the same galore (rather like the "artist impression" of the Pan Am space shuttle in a
2001: A Space Odyssey!!). However the environmentalist lobby took over and basicly closed the project down. That of course spelt doom for our Concorde as the Americans would not let that European plane fly over the States when they could not do that themselves with their own SST!
Concorde, in truth, never recovered from that as it could never achieve it's full potential with build numbers making it a viable proposition. With only British and French taking delivery of a relative few Concorde's, the Americans had scuppered it!!