after recording nine songs, imran had to leave for the us and mainul had to play both guitars to finish recording of the tenth song of the album. in those days recording were done in spools marketed in cassettes of sixty minutes. after recording ten songs the band found that there were still approximately nine minutes of recording space left for the cassette which should be filled. this gave birth to the eleventh and final rock strata song called kaalo raat. the song was based on the 1991 bay of bengal cyclone that hit and ravaged the coastal areas of bangladesh. arshad and mainul improvised with a few suggestions from mahbubur rashid and the song turned out be a little over eight minutes long. mainul left for the us after completing the guitar tracks.