Schematic for the assumed geometry of accretion structure for GX 339-4 from the LHS to the SIMS. The stable thin disc (grey) located far from the black hole is not variable. The fluctuations propagate inwards through the variable flow so the variabilities with different characteristic frequencies are produced in outer region (L₁, green) and inner region (L₂, blue) of the variable disc and the hot flow (L₃, red). When the variable disc closer to the ISCO, the hot flow merges with the inner region of the variable disc into the new merged variable flow.