The Beginner (After He Has Been Extemporising on an Instrument Not of His Own Invention [Browning])

LO! What is this that I make—sudden, supreme, unrehearsed—
This that my clutch in the crowd pressed at a venture has raised?
Forward and onward I sprang when I thought (as I ought) I reversed,
And a cab like martagon opes and I sit in the wreckage dazed.

And someone is taking my name, and the driver is rending the air
With cries for my blood and my gold, and a snickering news-boy brings
My cap, wheel-pashed from the kerb. I must run her home for repair,
Where she leers with her bonnet awry—flat on the nether springs!