Two Moons of Quatermass were spin-offs from Quatermass: they were flung out, in the long process of editing, as outs. Later, after Quatermass was done, I went back and edited them into the Two Moons.
They separated themselves from the main work because; the first Moon was too languid to work with Quatermass, and the second Moon was more playfully chaotic than Quatermass.
ST-201
Water Music, Quatermass, and Two Moons of Quatermass.