ok, I'll try to be as clear as possible: When we 'send' light through a real small puncture or trail, we are able to see that the light is bended to the outside. so light that comes in a straight line, will come out of this puncture in wider directions. the smaller the hole, the bigger is the bending. On school we learn this is a common feature of waves. But, this doesn't satisfie me.....what is the real complete explanation???????