Hi Gabi, it would probably help a lot if you could include some kind of sketch or drawing of what you are talking about, that would make it a lot clearer.

If you just want a shape to tile an area, like Burr mentions you can replicate that shape using Transform / Array / Grid, and then use Trim or a boolean to cut pieces that overlap with your boundary.

If you want to have circles that fill an area without any of them being cut, then that is a much different problem - MoI does not have any built in tools for that, and typically you will need to look for some specialized software to handle that kind of a thing. If this is what you are trying to do, try searching for "packing" or "nesting" type software.

- Michael