EMT Shelf V4

I wanted to make a shelf for a speaker, and while wood is nice, EMT Tubes are $3.37 for 10 foot! So I designed this. It's based on damping of Sin wave, the decay curves provide balance of support. I used 18mm Tubes, aka "half inch". The tubes are a bear to cut, so the caps cover any less than ideal cuts. I used miter saw with metal blade, tubing cutter might have been better idea. And the screw holes have .4 tubes around them so the walls will reinforce that area.