Ludwick Marishane, a 17-year-old South African, was with his friends in Limpopo when they started talking about inventing something to put on your skin so you don't have to take a bath. Ludwick thought that this was a great idea. He used his mobile to do some research on the Internet and he found some surprising facts.

Two point five billion people around the world haven't got clean water. This is a huge problem because dirty water can create terrible illnesses. One of them is trachoma (沙眼): eight million people all over the world get trachoma every year. They wash their faces with dirty water, get an infection and become blind. To stop trachoma, people don't have to take expensive medication. They don't have to take medicine. They have to wash their faces with clean water. That's it.

Ludwick started thinking. He wanted to make something to help people in parts of the world where it's difficult to find clean water. He did more research on his mobile, and he did some more thinking. Then Ludwick had a plan. He wanted to make a gel (凝胶) for people to put on their skin so they don't have to take a bath. He wrote the formula (配方) for the gel on his mobile phone. When he was at university, he never stopped thinking about his invention. He started to talk to other people about it, and three years later his dream came true. He made the gel and called it “DryBath”.

Ludwick Marishane is the winner of lots of prizes. People call him “one of the brightest young men in the world”. He is very happy about his success. DryBath is helping people stay healthy. And DryBath also helps to save water. That's important in many parts of the world where it's difficult to find clean water. Now he wants to invent other things, and he wants to help other young people to become inventors too.

Mr Smith was the manager of a hotel in Springfield. One weekend all of the hotels in the city were full because there was a large meeting. Late in the evening three men came into the hotel and asked for rooms. Mr Smith explained that because of the meeting, there were no rooms ready for use. The men were very unhappy because they had no place to stay in.

Mr Smith wanted to help them. He remembered that Room 414, a very small room, was empty. He asked them if they would share a room. The three men agreed. Mr Smith told them that the room would cost $30: $10 for each. Each of them gave Mr Smith $10, and they went up to the room.

Mr Smith soon began to feel sorry. “Thirty dollars is too much for that small room,” he thought. He called one of his men over and said, “Here is $ 5. Bring it to the man in Room 414. I’ve asked too much money for their room.”

The worker took the money from his manager. While he was on his way to Room 414, he started to think, “How can I divide $5? Well, I’ll give each of them only $1 and I keep $2. The men will be happy to get anything back. I’ll make a little money and Mr Smith will never know.” So he returned $1 to each man.

You see, there come a problem, each man had at first paid $10. After the worker returned them $1 each, each man had paid 9. There were three men, $9 x 3 =$27. The worker kept $2 —$27+$2=$29. Where is the missing dollar?

Tia Wimbush and Susan Ellis have been co-workers for a decade, and while they didn’t know each other well, they had a lot in common, both working in information technology at Children’s Healthcare of Atlanta and both dealing with the same medical stress at home: their spouses each needed a kidney transplant, and while Wimbush could have given her husband one of hers, she wasn’t an ideal match. Ellis, meanwhile, was no match at all for her husband.

One day, in the fall of 2020, the women saw each other in the office restroom and started chatting, lamenting that patients can wait five or more years for their name to come up on the national kidney cadaver donor waiting list. Both women worried their husbands didn’t have that kind of time.

Wimbush asked Ellis what her husband’s blood type was. He’s type O, Ellis replied.

Wimbush then said that her husband was type AB.

The women paused for a moment and looked at each other.

“I told Susan, ‘Wait a second-what are the odds that we’re both going through this with our husbands at the same time and we could also be in a position to help them?’” Wimbush says. “That’s when we both knew: We had to get tested.”

So they did. Antibody tests revealed that each woman was an excellent match for the other’s spouse. And in March 2021, seven months after that chance conversation, Tia Wimbush donated one of her kidneys to Lance Ellis, and Susan Ellis donated one of hers to Rodney Wimbush.

Christina Klein, a nephrologist and medical director of Piedmont Atlanta Hospital’s kidney transplant program, says it is extremely rare for two people to propose their own paired organ exchange and actually be a match for each other. “I’ve personally never seen this happen,” Dr. Klein says. “When we put pairs into large databases for national paired exchange programs, some pairs wait months or even years for a compatible match.”

The couples first met a few days before the surgeries when they came to the hospital for a final round of testing. Before that, they had chatted on FaceTime a bit. The surgeries lasted about three to four hours each and were a success, with no complications.

“It’s really just a story about simple kindness,” Susan Ellis says. “For us, it started with two people just being good humans. Now we’d like to tell people they can do the same.”

Rodney Wimbush says he will be forever grateful that his wife decided to bring up a conversation about blood types in the office restroom. “Susan and Lance are going to come with us to North Carolina for our son’s first college football game,” his wife adds. “I guess you could say we’ve skipped the friendship. We’re family now.”