In Insular Brythonic mythology, Gwythr ap Greidawl was a rival of Gwynn, the god of the underworld. They fought over a maiden named Creiddyland[?], who eloped with Gwythr but was kidnapped by Gwynn. Their rivalry represented the contest between summer and winter.
... the groove must not be lubricated. The acceleration of the gyroscope is best when the precession of the gyroscope is supported and amplified by wrist motion.
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