Regarding an instrument used in "Pilaf to Sono Buka"

[JulieYBM]

So, I'm listening to Pilaf to Sono Buka and about twenty-three or twenty-four seconds into the piece there is a series of 'boop-esque' sounds make in quick succession. Does anyone know how those sounds were created and if the technique has a name? This is something I have been meaning to ask about for a while and find it quite interesting.