e ---15----------12----------13------15----------12----------13------| b -------12--13------12--13------12------12--13------12--13------12--| g -------------------------------------------------------------------| d -------------------------------------------------------------------| a -------------------------------------------------------------------| e -------------------------------------------------------------------| e ---13----------------------12------13----------------------12------| b -------12--13--15--12--13------12------12--13--15--12--13------12--| g -------------------------------------------------------------------| d -------------------------------------------------------------------| a -------------------------------------------------------------------| e -------------------------------------------------------------------| (just keep repeating these 2 blocks together)