pacemaker
"A pacemaker is like a conductor that keeps every other musician on key"
"A pacemaker is a battery-driven form of life support. It belongs to the patient, not us. In this way, a pacemaker is like mechanical ventilation or renal dialysis. Though inside the body, the pacemaker is extra, unlike say a heart valve that has been endothelialized (grown into the body), and would take extraordinary measures to remove."
"The pacemaker is like the rhythm keeper to the heart as a percussionist keeps the rhythm in a music band. The artificial pacemaker is usually placed in the subcutaneous fat layer (a few inches below the skin in the chest)."

METAMIA is a free database of analogy and metaphor. Anyone can contribute or search. The subject matter can be anything. Science is popular, but poetry is encouraged. The goal is to integrate our fluid muses with the stark literalism of a relational database. Metamia is like a girdle for your muses, a cognitive girdle.