aHR0cHM6Ly9zdHJvbmdwaHlzaWNzLndpa2lzcGFjZXMuY29tL2ZpbGUvdmlldy9waHlzaWNzMi5qcGcvNTE5NjkzNzcvNTMzeDIxNC9waHlzaWNzMi5qcGc= Published February 10, 2018 at 533 × 214 in 02/05-02/09/18 (Con of Mom) PhySP18SS5.1.15 Basic elastic collision