Roller Coaster released their 4th album last week, with “Rainbow” as its title number. "Rainbow” features a staccato house rhythm backed up by solid bass, and the random emergence of an acoustic guitar. "Sad and Happy Story" features a melancholy melody in minor scale based on ever-repeating acoustic guitar riffs and heartrending lyrics written by Cho Won-sun, the vocalist of the band. The 8th track, "Close to You," reminds one of bright spring sunshine and yellow-mint grass, largely indebted to Cho's dreamy, nonchalant and sandy voice. Formed in 1999, Roller Coaster was first recognized for the song "Habit" in the first album, in which a speaker deals with the emptiness after a breakup. Although the trio has not once appeared on K-pop ranking television shows, their songs ranging from "Cheer Up, Mr. Kim" and "Love Virus" to "Last Scene" in the first three albums had a silent yet powerful attraction: The third album, "Absolute," sold as many as 150,000 copies. The members of the band insist on doing all their own writing, arranging, producing and engineering. The recording for the new album was also done at a home studio, with the exception of a couple of tracks that required special sound effects.