Forged in Fire season 8 episode 17
Episode title: Memory Game
Four smiths put their memory to the test when they are tasked with recreating an insanely complicated blade after looking at it for only 20 seconds. After an intense round of testing, the remaining two competitors return home to make one of the most unique weapons ever featured on the forge floor--the Elephant Tusk sword. The two weapons then will undergo some of the most brutal tests in Forged in Fire history, but only one will survive to win the title of Forged in Fire champion and a check for $10,000.
