Blockfield

Okay, imagine you have a very big and empty field, like a big playground. This field is called a blockfield, because we can divide it into small squares, like a checkerboard. Each of these squares is called a block.

Now let's imagine that we want to build something on this blockfield, like a house or a tree. To do that, we need to place these things on top of some of the blocks. We can choose any block to build on, but once we have put something on a block, we can't put something else on top of it. That block is now "occupied".

We can keep building more and more things on different blocks, until we have a whole village or city on our blockfield. But we need to be careful not to use up all of the blocks, because once every block is occupied, we can't build anything else.

That's the basic idea of a blockfield. It's like a big open space where we can build things on small squares called blocks. We can build as much as we want, but we need to make sure we don't use up all the blocks.