Reproduction of theoretically calculated fluorescent decay times. A: Simulation of time-dependent photon counts for single donor environments. The acceptor distances were between 1 and 10 nm. B, C: Simulation of fluorescent decay signals of equal amounts of FRET pairs (from A). Representative curves of simulations with one donor-acceptor distance fixed at 4 nm (B) or 6 nm (C) while for the other donor-acceptor pair the distance was variable and the distances are displayed in the legend. For better representation of the 6-nm experiment the curves are split in two plots. The amount of the two donors in each simulation was equal. No acceptor denotes a simulation experiment with donor only. Simulated values are depicted with symbols and the matching theoretical calculations as lines in the same color.