How to apply layers to physics?

I created layers called 'Ball' and 'Block'. I want Ball collide with Block, but not Ball with Ball. What should I do?
UPD:
I tried Project Settings>Physics 2D but with no luck:


Scene in debug view:

 

bump

 

First, you assign relevant layers. Then in physics settings, if I am correct, there is collision matrix. It uses pairs of layers, to match, which collisions are permitted.

So lets say you got balls and boxes layers. In matrix you need untick balls-balls pair.

 

This doesn't work.
Balls still collide each other.

 

Hmm, interesting.
I would expect to work.

May I ask, which version of Unity do you use? Your UI fonts looks odd-ish.

Oh, and again, my wrong sorry, since this is Project Tiny, there may be different approaches to things, which I am not familiar with.