There is a particular LED jack-o-lantern, which can scroll the message HAPPY HALLOWEEN.

Installed in this lantern is a 5×14 matrix of LED, spaced apart by printing out a grid on paper, taping it to the pumpkin, and drilling 70 holes into its face.

According to the creator of this machine, the hardest part of the whole process was inserting all the lights into the pumpkin through the back.