With your graphics programme you can re-work the proportions of any shape to suit the design you have in mind, even erase parts you don't want to keep. Then, with some added path-shapes you can paste extras on to eventually build your very own design.
If only I had an inherent drawing/sketching gene, but this is the closest I can get to making my own images. If you paper-cut your own designs, I hope you'll share your method of creating your own here with your comments.