Experimentally determined fluorescent signals. Symbols: feature block 1, blue upward-pointing triangles; feature block 2, cyan circles; feature block 3, green downward-pointing triangles; feature block 4, magenta squares; average of all feature blocks, solid black line. a) Fluorescent signals as a function of loop length (from loop length 0 (PM), to loop length 13) averaged over all loop positions. PM signal is set to 1. b) Hybridization signals as a function of loop position averaged over all loop lengths. Loop position 7 indicates that the loop is inserted after base number 7 of the probe motif counted from the surface.