Anvil
Anvils are extremely heavy. They are made in different sizes. The 17th century writer John Bunyan was a tinker (someone who mends pots and pans). He walked around the villages of Bedfordshire with a small anvil and a few tools on his back. His anvil was wedge-shaped, so that he could knock it into the ground when he needed to do a repair. His anvil is now in the John Bunyan museum in Bedford.