Diversions Manifold

Mountain biking (an all to rare occurrence for me these days) is not a purely physical exercise; the brain is given a real workout, too. I'll concede straight away that it's by no means an intellectual exercise - I'm not necessarily thinking of anything at all (also a rare occurrence, one to be encouraged). But sometimes I become aware of the sheer mass of calculations that the brain is performing whilst I'm on the bike. It's thinking almost as hard as the legs are pumping. Of the many types of calculations buzzing around in my head, the most satisfying for me is the "hit or miss" question. I'm pedalling along a trail, at best upwards, and there's a rock in the way. Now, I can miss the rock with my wheels simply by steering away from it. But if things are tight and there isn't much room for manoeuvre, I start wondering if I'm going to bottom out with my pedals - which is usually a worse situation than hitting a rock with the wheel. Is t