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Perpetua lex est
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perpetual motion
-- perpetual motion machine --
Perpetual screw
perpetual warrant
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Perpetuating testimony
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Perpetuities are odious in law and equity
Perpetuity
perphenazine
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perpetual motion machine
| Noun | 1. |  perpetual motion machine - a machine that can continue to do work indefinitely without drawing energy from some external source; impossible under the law of conservation of energy |