Both songs start with a similar percussive pattern, and the keys are not identical, but within a half-step apart (Ebish, E). "Rock Your Baby" was released in 1974, and "Heart of Glass" in 1979. The "B" section of "Heart of Glass" is clearly influenced by "Rock Your Baby". Both lyric melody lines start on the same note, and although RYB has a longer, more intricate chord pattern, technically, all the chords of HOG are in there. Start @ 1:43 in "Heart of Glass" for comparison.