The clarinet is uncommon, but not unheard of, in rock music. Lightning and thunder are virtually unheard of. They are unseen and unheard by the people around them. It was almost unheard of before the song. Snowfall is rare but not unheard of. Snow is almost unheard of and typically does not accumulate. Most of these recordings remain unreleased and unheard by the public. Each documentary contains rare footage and previously unheard dialogue. An attempt to regain the crown for an unheard of sixth time proved beyond Robinson. This edition also included unreleased 12-inch remixes and previously unheard demos. These methods resulted in a clarity previously unheard in this type of multitrack recording. Farm machinery and chemical fertilizers were nearly unheard of. The publication of "Cries Unheard" was controversial because Bell received payment for her participation. But a female wizard is something completely unheard of on the Discworld. Marriage with these slaves was not unheard of or prohibited.