Opus incertum

Opus incertum is like building blocks made out of stone. Imagine you are playing with big lego blocks, except these blocks are made out of stone and are not as easy to move around. Instead of fitting perfectly together, each block is a little different shape and size, so when you put them together they leave small gaps between them. This is what makes opus incertum unique and different from other building styles. But even though there are gaps between the blocks, they still fit together well enough to make a strong and stable wall. It's like building a big puzzle, where every piece is unique but fits together perfectly enough to make a complete picture.