i. Platform method to create pop-up

When you draw a heart or a duck on the sketchpad, Pop-up Maker erases some part of the bottom and creates platform with folding lines and cutting lines. The following pictures show how Pop-up program generates a platform; 1) a user sketches a heart in the sketchpad. 2) Program erases the bottom part of the heart 3) Programs creates folding lines (blue) and cutting lines (red).