To facilitate studies of neural network architecture and formation, we generated 
three Drosophila melanogaster variants of the mouse Brainbow-2 system, called 
Flybow. Sequences encoding different membrane-tethered fluorescent proteins were 
arranged in pairs within cassettes flanked by recombination sites. Flybow 
combines the Gal4-upstream activating sequence binary system to regulate 
transgene expression and an inducible modified Flp-FRT system to drive 
inversions and excisions of cassettes. This provides spatial and temporal 
control over the stochastic expression of one of two or four reporters within 
one sample. Using the visual system, the embryonic nervous system and the wing 
imaginal disc, we show that Flybow in conjunction with specific Gal4 drivers can 
be used to visualize cell morphology with high resolution. Finally, we 
demonstrate that this labeling approach is compatible with available 
Flp-FRT-based techniques, such as mosaic analysis with a repressible cell 
marker; this could further support the genetic analysis of neural circuit 
assembly and function.