Cast glass. The inspiration for the work comes from 'The Wind Hover' written by the priest-poet Gerard Manley Hopkins in 1877.
"I caught this morning morning's minion, kingdom of daylight's dauphin, dapple-dawn-drawn Falcon, in his riding
Of the rolling level underneath him steady air, and striding
High there, how he rung upon the rein of a wimpling wing
In his ecstasy! then off, off forth on swing,
As a skate's heel sweeps smooth on a bow-bend the hurl and gliding
Rebuffed the big wind. My heart in hiding
Stirred for a bird -- the achieve of; the mastery of the thing!
..."
