Well, I suppose you're right Pappenheimer, so I'll start at the beginning.

This is the official website of the free game:
http://complex.ovh.org/

And this is the official website of Crayon Physics:
http://www.crayonphysics.com/

The free game was called PhysicDraw and it was made a good year or so ago, long before the team that created Crayon Physics ever started work on this project. Sure, Crayon Physics is a little more refined and it has an actual goal, but the actual premise is almost a complete rip-off of this free game.

The creator of PhysicDraw is named Flavien Clermont, and his personal website can be found at:
http://flavien.clermont.free.fr/

The creator of Crayon Physics refers to himself as Petri Purho, also taken from his website:
http://www.crayonphysics.com/

I think I can safely assume that these guys are not the same people.