To the annoyance of parents everywhere, children love playing with tape measures. They will lock the extended tape in place and notice how a slight curve keeps the metal strip rigid. Then they will release the lock and delight in how a spring retracts the tape with a satisfying thwack.

Roboticists at the University of California, Los Angeles have been playing with tape measures, too. They have discovered that the rigid but bendy tape can be used as a new type of limb that acts something like a spider monkey’s arm or an octopus’s tentacle.