Why does science refuse to recognize the strange physical properties of duckunders that cause them to lower themselves one inch per year? Probably something going on at the sub-atomic level. I know this to be a fact; 20 years ago I would plant one foot under the duckunder, bend, turn and, presto, I was on the other side. Now I squat down, shuffle an inch at a time then slowly press myself up. Durn thing lowered itself - no other explanation. But I am fighting back: Pipe insulation snapped to the bottom of the "L" girder helps. But the breakthrough invention is the "Geezer-glider" - just some old casters attached to a footstool.