Nature has given us quanta, like photons and electrons, which can be described by quantum mechanics.
They are quantized, and have amplitudes; they can exist in superpositions, and they become entangled.
If carefully controlled, we can turn these quanta into qubits, the basic resource for a quantum computer.
Quantum circuits form the basis from which we code quantum programs. They are also known as scores,
because of their similarity to musical notation. We can call them either circuits or scores. We create scores
by building primitives, which are like individual bars of music.