Two Young Genndy Tartakovsky Cartoon Boys

On the red corner is Young Jack, the kid version of the title character of my favorite action cartoon, Samurai Jack, which is also Genndy Tartakovsky’s magnum opus:

And on the blue corner is Dexter, the title character of my favorite comedic cartoon Dexter’s Laboratory, which is also Genndy Tartakovsky’s first hit show for Cartoon Network:

First off, I have this question:

What are the differences between the two young Genndy Tartakovsky cartoon boys that I’m talking about?

Well, can you take a shot at spotting the differences between Samurai Jack’s Young Jack and Dexter’s Laboratory’s Dexter?