Oh boy i bet the air was blue ,..thankfully it didn't fall on top of you these things are not expected to happen but wow they do,..if you get the Arch straightened out,..someone may never notice .

If its any consolation we guys make terrible mistakes as well,..purchased a new door that needed a few inches cut off to fit,..measured and marked the cutting line,..decided to place the door on a Teak Coffee Table,..couldn't figure out why it was so hard to saw but didn't think anymore on it,..lifted up the finished project and discovered i had cut off four inches off the end of the Coffee Table sanded it smooth and hoped nobody would notice,..it was three months later that my Wife asked,..was that Coffee Table always like that,..one end was short of the legs by eight inches the other was short by four inches,..i owned up