ScientistsattheCornellUniversityinIthaca，NewYorkhavecreatedsmallrobotsthatcanbuildcopiesofthemselves。Self－replicatingrobotsarenolongerthestuffofsciencefiction。

Eachrobotconsistsofseveral10cmcubeswhichhaveidenticalmachinery，electromagnetstoattachanddetachtoeachotherandacomputerprogramforreplication。Therobotscanbendandpickupandstackthecubes。

Althoughthemachineswehavecreatedarestillsimplecomparedwithbiologicalself－reproduction，theydemonstratethatmechanicalself－reproductionispossibleandnotuniquetobiology，HodLipsonsaidinareportinthesciencejournalNatureonWednesday。

Heandhisteambelievethedesignprinciplecouldbeusedtomakelongterm，self－repairingrobotsthatcouldmendthemselvesandbeusedinhazardousScientistsattheCornellUniversityinIthaca，NewYorkhavecreatedsmallrobotsthatcanbuildcopiesofthemselves。Self－replicatingrobotsarenolongerthestuffofsciencefiction。

Theexperimentalrobots，whichdon‘tdoanythingelseexceptmakecopiesofthemselves，arepoweredthroughcontactsonthesurfaceofthetableandtransferdatathroughtheirfaces。Theyself－replicatebyusingadditionalmodulesplacedinspecialfeedinglocations。

Themachinesduplicatethemselvesbybendingoverandputtingtheirtopcubeonthetable。Thentheybendagain，pickupanothercube，putitontopofthefirstandrepeattheentireprocess。Asthenewrobotbeginstotakeshapeithelpstobuilditself。

Thefour－modulerobotwasabletoconstructareplicain2。5minutesbyliftingandassemblingcubesfromthefeedinglocations，saidLipson。