Back around 1990, when Tiny Toon Adventures was in production, one of the staff artists drew a big group caricature of the whole crew (which appeared, colorized, in the "K-ACME TV" episode):
And by "staff artist," we mean specifically Bruce Timm, who would later become a star with Batman the Animated Series. In fact, if you recall that he was also the visual inspiration for the Mad Bomber in the Gray Ghost episode of BtAS, you can probably pick his self-portrait out very easily.
But more importantly, we'd like to draw your attention to two particular people in this drawing, found at opposite corners: writers Eddie Fitzgerald and Tom Minton:
Tom and Eddie's personalities were as different as the drawing suggests, with Minton being low-key and quiet, and Fitzgerald loud and boisterous. They shared an office, and so everyone else would just hear Tom's quiet mumbling from inside, then Eddie's raucous laughter. Tiny Toons' creator, Tom Ruegger, would find himself wondering what was going on in there - were they secretly planning to take over the world? So when he needed more characters for Animaniacs, Ruegger took Bruce Timm's drawings of Minton and Fitzgerald, drew big ears on them, and Pinky and the Brain were born.