Maxwell's Fishpond Paul Kinsler, Jiajun Tan, Timothy C. Y. Thio, Claire Trant, Navin Kandapper Department of Physics Imperial College London, Prince Consort Road, London SW7 2AZ United Kingdom. Eur. J. Phys. 33, 1737 (2012) arXiv:1206.0003 doi:10.1088/0143-0807/33/6/1737 Most of us will have at some time thrown a pebble into water, and watched the ripples spread outwards and fade away. But now there is also a way to reverse the process, and make those ripples turn around and reconverge again, ... and again, and again. To do this we have designed the Maxwell's Fishpond, a water wave or ``Transformation Aquatics'' version of the Maxwell's fisheye lens [Tyc et al. NJP 2011, Luneberg 1964]. These are transformation devices where wave propagation on the surface of a sphere is modelled using a flat device with spatially varying properties. And just as for rays from a point source on a sphere, a wave disturbance in a Maxwell's fisheye or Fishpond spreads out at first, but then reforms itself at its opposite (or complementary) point. Here we show how such a device can be made for water waves, partly in friendly competition with comparable electromagnetic devices [Ma et al., NJP 2011] and partly as an accessible and fun demonstration of the power of transformation mechanics. To the eye, our Maxwell's Fishpond was capable of reforming a disturbance up to five times, although such a feat required taking considerable care, close observation, and a little luck.