When the sample is reversed and corrected for pitch "Keep a smiling face" plays at 2:27 in Sixtyten, taken from 1:10 in On Your Face. [3]
Ending
The separate vignette at the end of the track is believed to be a composition named "Blueberry".[4]
Trivia
Sixtyten is 70 (a literal translation of the french word for seventy 'soixante dix'). You'll hear this in Aquarius too. A reference to Music70, BoC's own label. See comments on The Smallest Weird Number in Geogaddi.