Thread for certain patterns don't exist within a box

[David]

Geez, anyone might have used lifesrc or WLS, right? What a patience and time required for them.
These programs search for certain patterns within a bounding box, and there may be no results.
If someone finds a new object, it is a great discovery. But if doesn't, isn't it still good, so everyone will know that certain patterns don't exist within the bounding box?
So, this thread is here for non-existing patterns.
My discovery is that p7 oscillator with 8-fold symmetry doesn't exist within 15x15 bounding box.
What's yours?