This has nothing to do with LASER (Light Amplification by the Stimulated Emission of Radiation), nor a concerto by a composer whose work I like, nor the word flerd.
From the online OED (the new website of which, despite its many charms, places the word scroll list on the right and in a smaller, less legible form that includes a somewhat bouncy and rather irritating automatic scroll function; the previous site's colors and text bits were more pleasing to the peepers--not as many trips to the online OED for me this coming year):
Flerry: to split slate.
1865 J. T. F. Turner Familiar Descr. Old Delabole Slate Quarries 13 The better the quality of the slate, the easier will it flerry, and also cleave.