20 minutes recumbent bike.
70 minutes deep pool running. ![](http://www.neatorama.com/wp-content/uploads/2010/04/not-a-spiral1.jpg) The blue elements in the image above appear to be a arranged in a
continuous spiral, but in fact they form a series of concentric
circles. Your brain will argue so strongly for a spiral that you may
need to run your mouse cursor around the circles a few times to convince
yourself. |