Pictureacomputerscientist,staringatascreenandclickingawayfranticallyonakeyboard,hackingintoasystem,orperhapsdevelopinganapp.Nowdeletethatpicture.InOnceUponanAlgorithm,MartinErwigexplainscomputationassomethingthattakesplacebeyondelectroniccomputers,andcomputerscienceasthestudyofsyst