It’s a project by John Cage which is being played by an organ in the church of St. Burchardi in Halberstadt, Germany, and began in the year 2000. It’s only reached it’s sixth note this year, and won’t reach another until November. It will take 639 years to come to completion.
In view of our fast moving age, this piece of music is a way of trying to slow down our hectic lives.
The “discovery of slowness” and the planting of a “musical apple tree” can be understood as symbols of confidence in the future.
I can think of no word but “excruciating.”