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].
Setelah drum - drum bergerigi logam itu bergerak sepanjang lebar mesin, seluruh peralatan itu ​ — drum, kaki hidraulis, dan atap pelat baja ​ — bergeser maju setengah meter.