Input (grade 12): Queen Victoria of England (1819 - 1901) had a billiard table that was heated using zinc tubes, although the aim at that time was chiefly to keep the then-used ivory balls from warping.
Output (grade 8): Queen Victoria of England (1819 - 1901) had a billiard table that was heated using zinc tubes, At that time, though, the reason for the heating was different. The heat was used to keep ivory balls from going out of shape (warping).