Ann posted instructions in our forums for creating an electric kistka (wax pen) for the Eggbot for traditional Pysanky egg dying techniques. She used nichrome wire, krylon tape, a modified kistka, and a 2xAA battery holder with a switch and described how to mount it in the Eggbot. She posted a couple of designs to Thingiverse demonstrating the technique including the rose design pictured above.
For a Humpty Dumpty design, she wrote up how she made it:
Using eggbot and custom electric kistka, plotted the Humpty Dumpty picture and text on an egg. First plotted outline, dyed brick, colored in bricks by hand with kistka, dyed blue.
You can check out her other designs for the Eggbot on Thingiverse.