1960s: Person draws line through drawing of cone on paper, draws dashes at angle away from cone, draws another line away from cone, shades in shadow area.
1960s: Person draws line through drawing of cone on paper, draws dashes at angle away from cone, draws another line away from cone, shades in shadow area.
1960s: Person draws line through drawing of cone on paper, draws dashes at angle away from cone, draws another line away from cone, shades in shadow area.