So, this one is a bit tricky I think. I have set up a grid (30x30). And you can place "room" sprites ( w: 30, h: 30). They are all aligned to the grid. so their coords are 30,0 / 60, 0 etc. A real room should be made out of a few "room" sprites. now, I would like to detect if a room is at least made out of 3 by 3 sprites. Since you can have multiple rooms this has to be checked each time a sprite is placed. I have been googling for some time now and read some answers in similar directions which are about floodfill algorithms. Since my rooms are constant on coords and sprite w/h, i think, it can be a bit easier than this. Are there any suggestions How this can be realized into phaserjs? Need some food for thought. ~happy new year to all of you. regards