talk. • Alice: Do you like the sushi today? • Alice starts waiting Bob’s response • Bob receives the message, starts thinking how to respond in Japanese. • Bob: Sushi wa umai desu. • Alice receives the message, starts thinking what to say next.
• Bob waits for Alice to Talk. • Alice ask Bob: is_sushi_good? • In Bob receive block, receive the message, send message “sushi_score” to self(Bob), then waiting Bob to respond. • Bob can’t receive the “sushi_score” message because he’s already in a receive block, Bob waits forever, program hanged.