Original sentence: Brunel may be credited for the idea of using a shield, but it was Greathead who designed the circular shield that has since been used in most subsequent tunnelling projects.Brunel's shield was rectangular, while Greathead's was circular, though the face was still dug out by manual labour to begin with.Design of the Greathead Shield derived from Brunel's original idea.Greathead's patented Shield for Tunnelling Soft Earth used pneumatic compression in the tunnel to ensure better safety for workers.However, there were sufficient design changes to make it distinguishable from Brunel's shield, allowing a patent application for Greathead's design.The 'second edition' of his shield used hydraulic action at the face to create slurry
Edited sentence: Brunel may be credited for the idea of using a shileld that was rectangular in shape, but it was Greathead who designed the prototype circular shield that has since been used in most subsequent tunnelling shields since then.Brunel's shield was rectangular, whilst Greathead's was circular.Each man had a massive influence on tunnel design for the rest of human history since then and each needs be accredited that in the annals of history as the men who made tunnels safe and reliable.Greathead's patented Shield for Tunnelling Soft Earth was substantially different in design and safety and that it used pneumatic compression in the tunnel to ensure better safety for the workers.Greathead's shield design was circular, but the face was still dug out by manual labour to begin with.However, there were substantial design changes that made it distinguishably and therefore different from Brunel's shield considerably that the patent was applied to Greathead's design.The "second edition" of his shield used hydraulic action at the face to create slurry.The Brunel-Greathead shield did not exist.The Greathead Shield is a design that was derived from Brunel's original idea