(1) Fourth suit forcing
This deal is from an online EBU duplicate.
After North showed clubs and spades, South set up a game force by bidding the fourth suit. When North rebid clubs and later showed the diamond king South was fairly certain that North had six clubs. A series of control bids was followed by Roman Key Card Blackwood. With all the controls held South asked for kings. When North denied the spade king South could only count 12 tricks so settled for six notrump.
West led a diamond, won in dummy. Now two top hearts followed by four rounds of clubs and the end position below was reached. East and West can afford to throw a spade on the fifth club, but when the last club is played East cannot afford a spade (or South can take the spade finesse) or a diamond, so must throw a heart. South throws his low diamond and then two rounds of diamonds squeeze West between spades and hearts for the overtrick.
This is a non-simultaneous double guard squeeze (I think).