Rigidity (mathematics)

Rigidity is like when you put together a very tricky puzzle and it stays together really tightly no matter what you do to it. It means that the way the different pieces fit together is very specific and can't change even a little bit or the whole puzzle falls apart. In mathematics, rigidity works the same way, but instead of puzzle pieces, we use things called shapes and numbers. We can say a shape or number is rigid if it can't be changed even a little bit without changing its whole identity. It's like trying to turn a circle into a square, it just doesn't work because the two shapes are very different and can't be made into each other. So when we say something is rigid in math, it means it's very specific and can't change without losing its important qualities.