Product Development Using Bio-mimicry Design Spiral Approach of Swimming Aid Purwaningsih Ratna, Rahardjo Danu, Budiawan Wiwik, Adi Wicaksono Purnawan and Santosa Haryo E3S Web Conf., 73 (2018) 08007 Published online: 21 December 2018 DOI: 10.1051/e3sconf/20187308007