In the 70s and 80s there were many portable shacks being used on Lakes Mendota and Winnebago that looked like a clear plastic bubble, or more accurately, an oval shape like an egg cut in half lengthwise. They were covered with clear plastic like visqueen and had 5 or more bent conduit supports that were all joined and hinged in the middle. The thing folded in half and when set up, one or two guys could sit and fish in it. Sunlight shined through it and warmed it up. What were these shacks called, who made them, and is it still possible to buy one somewhere? Thanks.