A rare preparatory triple squeeze, followed by a double squeeze. Normally, the ending requires two double menaces (guarded by both opponents) and a one-card menace (guarded by one opponent). The one- card menace must be over the relevant opponent, and declarer has top winners for all the remaining tricks but one.
First, see that the requirements are present: Declarer has six top winners (three ace-kings), doubly guarded menaces with entries to the threats in both minors and a singly guarded menace in spades (the king over East’s ace).
The lead of the ♥A squeezes East in three suits. To avoid conceding a trick immediately, he must discard from one of his minor suits. This gives West sole responsibility for guarding that minor suit, thereby preparing the way for a double squeeze.
South next plays the king and ace of whichever minor suit East discards, and then leads the ♥K, which creates a double squeeze on both opponents.
