CLU looks like his dad because his programming was written by his dad, Quorra tells him when Sam asks. It's the same for other programs, too - though obviously, as an ISO, she herself doesn't have an equivalent user.
"So," Sam sums up, once she's finished, "If I happened to have a program created by me, and I put it on the Grid, it'd look like me?"
She confirms it, and that's all the information Sam needs to get his own computer hooked up to the Grid.
ooo
It takes a few days before Sam manages to get everything synced up correctly, and all in all it's over a week before he gets a chance to return to the Grid.
"It's called Legacy," he tells Quorra as they're setting everything up and making sure it's secure. "Y'know, the program I wrote. It doesn't exactly do much, but it was... I made it specially to get ENCOM's OS12 onto the net, I just ended up calling it Legacy since it was helping to carry on with my dad's." He's awkward about it now, in a way he hadn't expected himself to be, but Quorra just smiles as she activates the laser, and the next thing he knows, he's coming to in the Grid.
He's immediately confronted by himself, and Sam inhales sharply. He hadn't expected the program to find him quite so quickly, and even having been told about it doesn't stop it from being incredibly surreal.
There are differences, subtle but there, and with the program staring at him so intently, they're easier to pick up on than they would be otherwise. There's something softer about the program's features, almost like... almost like Sam's face had been that one time in CalTech when a couple of the girls had managed to convince him to let them give him a makeover, he realises, and he's not even going to ask why his program-self apparently comes with makeup as standard. The circuitry is different from Sam's too; a little more complex, the individual lines a little thicker.
After a few moments the program sits back on his - its? - haunches and grins at him, and Sam has to wonder if he looks quite that dorky when he grins. "You're my user," the program tells him, and it's like hearing a recording of his own voice.
"The one and only," he answers, grins back and he can only imagine what this must look like, him and makeup-wearing-program-him grinning at each other like idiots. And then the program edges closer, and Sam breathes out Legacy, and without any real conscious decision made between them, their lips are touching. It sparks, like overloading, and Sam groans against Legacy's lips as the program reaches up and digs its fingers into his circuitry.
He'd wanted to meet his program for the novelty of it and a bit of a laugh, not a chance for a fuck with someone with his own face, but with Legacy's hands ghosting over his circuits he can't for the life of him imagine why he'd felt that way. Sam isn't exactly sure how to have sex when he can't even get their suits off, but Legacy certainly seems to know what it's doing. It digs its fingers into Sam's circuits hard so that he jerks forward, reaches up to return the favor and grins when the program wriggles against him with something like a growl.
Between the inexperience both of them have with doing things like this, and how enthusiastically they're both going at it, it doesn't last as long as Sam would prefer, but frankly it's the best sex Sam has ever had, and Legacy certainly seems to have enjoyed it, basking in the slowly-fading light of their circuits.
When the program stands up, turning away and sorting out its ruffled hair in the reflective surface of a nearby window, Sam watches it, grinning and commenting, "You know your circuits make a smilie face on your ass, right?"