Joseph Yoder is a person who is really good at something called software design. Software design is like building a house, but instead of using bricks and cement, we use things called code and computer programs. Joseph Yoder knows how to make the code and programs work really well so that when people use them, they don't have problems.
Just like you have different toys and games that you like to play with, there are different ways to make software. Joseph Yoder is famous because he came up with a special way of making software called "Design Patterns". Imagine you have a bunch of Legos and you want to build a car. You can use the same pieces in different ways to make the car look different. Design Patterns are like a list of instructions on how to use different pieces of code in different ways to make different software. It makes it easier for people to build software that works well, looks good, and is easy to understand and use.
Joseph Yoder is like a teacher who teaches other people how to make software using his special way of doing it. He also travels around the world to talk to other people who work with software, and he shares his ideas with them so that they can make better software too. By doing this, he has helped a lot of people make better software and make their customers happy.