When the splint edge is reached, the next layer should be folded back on itself to create the subsequent layer.
Or that other one from Friends, Lisa Kudrow? Black lines indicate the ends of the intended splint.
The gang is putting on a musical Charlie wrote and he casts Mac in the lead role.
Both characters are babies, though, so maybe this is more a meta case of? Thus, some viewers were when Craig and Manny started hooking up.