Sequence identification by hybridization. Three different hairpins (marked as molecule 1, 2, 3) were identified by two different oligos (marked as oligo1 and 2) (see Methods). Left panel: Experimental traces recorded during hairpin open-close cycles. To show the corresponding blockage, oligos 1 and 2 were added sequentially into the solution: oligo 1 hybridized on molecules 2 and 3, while oligo 2 hybridized on molecules 1 and 2. Right panel: Histogram of blockages from oligos 1 (orange) and 2 (blue) on each molecule, while the full extension of the molecule is shaded in grey.