Filmmakers Hannah Walsh and Emma Puchniak struck gold when they decided last year to make a documentary on Dutch-Canadian swimmer Betty Brussel, following her with their cameras ever since, the plan to release the end product some time in the autumn. Her story was already a joyous one before last weekend, but then she only went and broke three world records at a meet in British Columbia. There’s a good chance that you heard about her feat because it popped up at the end of a bunch of bulletins during the week, in that ‘….and finally’ section, the newsreaders sounding...