A good footslogging is part of many scientists’ tool kit. Tesla dreamed up the alternating-current motor during a stroll through the Városliget, or city park, in Budapest.44 To ponder difficult problems, Darwin walked down a gravel path called the “sandwalk” near his home in Kent, kicking up stones along the way.45 The physicist Werner Heisenberg devised the uncertainty principle during a late-night walk through a park in Copenhagen.
