Cinderella pumpkins are bright orange and somewhat squat. Choose one with a clean, flat base, which will serve as the clock's face. The design is carved with a linoleum cutter, which removes only the outer flesh.
Size clock-face template as needed to fit pumpkin, with the center of clock face aligned over the center of base. Print, and trim excess paper around template.
Cut a hole around pumpkin stem, large enough to fit glass jar, with keyhole saw.
Clean the inside of pumpkin with fleshing tool, removing seeds, pulp, and fibers.
Affix clock-face template to pumpkin's base with masking tape. Using awl, transfer designs to pumpkin by poking holes around blackened areas and numbers. Remove template.
With linoleum cutter fitted with a No. 2 blade, carve numbers and face, exposing flesh without cutting all the way through. For finer details, switch to a No. 1 blade; for larger sections, use a No. 3 blade.
Wrap lights evenly around jar, securing strands with tape so that lights don't touch. Set jar inside pumpkin to test design. If some details appear less bright than others, remove lights and scrape more flesh from inside using fleshing tool.
Size clock-hands template as needed. Print, and cut out with scissors. Trace onto black card stock, and cut out. Align bases of hands. Secure them to the center of clock with sewing pin.