This design was inspired by DesignMakeTeach's excellent post "Sharpie to 3D Print in 30 Minutes" on his blog http://designmaketeach.com. Draw on paper with a Sharpie, take a photo, change to bitmap and save as an .svg file in Inkscape, load into Tinkercad, download as .stl and print. For more detailed instructions see the link below. http://makerhome.blogspot.com