Here's a laughing dog:
We'll call him Fido.
Fido is producing a laugh: "HAHAHAHAHA".
Here's another laughing dog:
We'll call this one Rover. Rover is entirely identical to, but separate from, Fido.
Rover is also producing a laugh: "HAHAHAHAHA".
The laugh Rover produces is identical to the laugh Fido produces, but it is produced by Rover, not Fido. That is the only difference between the laughs. You cannot distinguish between the laughs, but if Rover and Fido are laughing at the same time there will be two laughs, not one.
Here are the two laughs:
"HAHAHAHAHA".
"HAHAHAHAHA".
Note that while they are entirely identical, there are two of them.