Solution - a clock that not only measures the passage of time, but serves as a stern reminder of mortality.

From a distance, the clock looks like a miniature coffin, propped up on a miniature tombstone. When you open the lid of the coffin, you see the black clock face with a miniature human skull in the center, and hands made of miniature human legbones. The bones gleam white against the black background as they move slowly toward eternity.

On the hour, the clock chimes with the sound of a tolling churchbell. Then the skull speaks the time in a sonorous whisper.

On the tombstone is inscribed the old epitaph:
My Dear Friends as You Pass By
As You are Now, So Once Was I.
As I am Now, You Soon Must Be.
Prepare Yourselves to Follow Me.

The "Catacomb Cuckoo Clock" is a bit more whimsical; it has an orchestra of skeletons (Mexican day-of-the-dead figurines) that pop out once an hour and play "When the Saints Come Marching in." On the tombstone of this one is inscribed "Had we world enough and time..." by Andrew Marvell. Or Emily's "Goodbye" speech from "Our Town."