Treasury Secretary Janet Yellen joked that she repeatedly practiced writing her own signature before it appears on bills next year after her predecessors’ were forced into do-overs because of their messy penmanship. “I knew this was something you could really screw up and I wanted to get it right, and I practiced and I practiced,” Yellen told Stephen Colbert late Wednesday. Yellen explained that former treasury secretaries Tim Geithner and Jack Lew both had to redo their signatures after people mocked them for being unreadable. Yellen added that she will travel to Fort Worth, Texas, next week to see the first bills printed with her signature.