After the drums with metal spikes travel the width of the machine, the whole contraption ​ — the drums, the hydraulic legs, and the steel - plated roof — ​ slides itself forward two feet [half a meter].
Kui metalloradega trumlid on masina laiuse läbinud, nihkub kogu mehhanism – trumlid, hüdraulilised jalandid ja terasplaatidest lagi – poole meetri võrra edasi.