The vline object is used to create ramps from one value to another value. Like a previous example, we will use the writesf object to write to external file.
A trigger bang bang bang bang is used to (1) open a file for writing, (2) starting a delay of 50 millisecond to end writing, (3) starting a 50-ms ramp from -1 to +1and (4) start writing.
The audio signal is a ramp from -1 to +1. This is not meant to be listened to, instead it is used to control an audio signal, such as attack and release of a note.
The output is a mono signal of 0.05 second duration: