Select a picture from a magazine or from your photo album and cut it in half. You can split the image horizontally or vertically or you can curve the path as you wish. Glue the split image on to a drawing paper so that you can draw the missing part.
You can try to draw the missing side realistically or you can use imagination to invent an imaginary continuum.
Materials: paper, glue, pens, pencils, scissors, picture from a magazine or newspaper or a photo