say we have closed system (box) consisting vacum and one mechanichal clock, wound to have (potential) energy (within spring) for say ten revoluntion for second hand in the begining. now when watch is allowed to have ten revolution of second hand and then it stops at the same location at it started, In the system, we should be having some heat energy released due to friction of mechanism and one dead clock. now is the energy of the system at the initial stage and final stage is same? has some energy lost in doing mechanical work, as not all energy is converted into heat? what is the disorder in system?