Sonu was so playful that he often forgot many things. Nilu was one of Sonu’s good friends. They were classmates and studied
together. During holidays, Nilu often met Sonu in a park.
Once, when they were playing in the park, Nilu saw a black thread tied to Sonu’s wrist. Nilu never saw Sonu wearing any bands
or threads on his hand before. Although initially hesitant, Nilu finally asked Sonu why he was wearing a black thread with a big knot!
Sonu said, “It was tied by my mother. Since I have this forgetful habit, my mother tied this knot to remind me that I should not
forget to post her letter!”
Nilu then asked, “Where is the letter, you have nothing in your hand and you are not carrying any bag!”
Sonu laughed and said, “My mom forgot to give me the letter that I was supposed to post!”
Both of them found this funny, and were rolling on the ground with laughter!