This is the baptismal font at my church.
The stained glass window doubles as a door. When it's open, you can see little steps leading from the water to a staging room that lies behind.
What you can't see is that the overhead light in that staging room is set pretty far back. Far enough, in fact, that if someone stands at the top of those stairs, that person will be backlit. So that if the window is closed, the congregation will see that person in stained glass silhouette.
And if, after dunking his sheep, that young pastor is impatient to get out of his wet clothes, that congregation will see the stained glass shadow of their spiritual leader shuck off his drawers and briskly towel off before donning a pair of dry pants.
Best baptism, ever.