```8 7 GfsSimulation GfsBox GfsGEdge {} {

# Stop the simulation at t = 15
Time { end = 15 }

# Use an initial refinement of 6 levels (i.e. 2^6=64x64 for each box)
Refine 6

# Insert the solid boundary defined as x*x + y*y - 0.0625*0.0625 = 0
# (i.e. a cylinder of radius 0.0625 centered on the origin)
Solid (x*x + y*y - 0.0625*0.0625)

# Add a passive tracer called T
VariableTracer {} T

# Add diffusion to tracer T
SourceDiffusion {} T 0.001

# Dirichlet boundary condition for T on the cylinder
SurfaceBc T Dirichlet 1

# Set the initial x-component of the velocity to 1
Init {} { U = 1 }

# Adapt the mesh using the vorticity criterion at every timestep
# down to a maximum level of 6 and with a maximum tolerance of 1e-2
AdaptVorticity { istep = 1 } { maxlevel = 6 cmax = 1e-2 }

# Adapt the mesh using the gradient criterion on variable T at
# every timestep, down to a maximum level of 6 and with a maximum tolerance of 1e-2
AdaptGradient { istep = 1 } { maxlevel = 6 cmax = 1e-2 } T

# Set a viscosity source term on the velocity vector with x-component U
# The Reynolds number is Re = D*U/Nu = 0.125*1/0.00078125 = 160
# where D is the cylinder diameter (as defined in cylinder.gts)
SourceDiffusion {} U 0.00078125
SourceDiffusion {} V 0.00078125

# Writes the time and timestep every 10 timesteps on standard error
OutputTime { istep = 10 } stderr

# Writes the simulation size every 10 timesteps on standard error
OutputBalance { istep = 10 } stderr

# Writes info about the convergence of the Poisson solver on standard error
OutputProjectionStats { istep = 10 } stderr

# Pipes a bitmap PPM image representation of the T field at every other timestep
# into a conversion pipeline to create a MPEG movie called t.mpg
# Sets the minimum used for colormapping to 0 and the maximum to 0.4
OutputPPM { istep = 2 } { ppm2mpeg > t.mpg } {
min = 0 max = 0.4 v = T
}

# Pipes a bitmap PPM image representation of the T field at time 15
# into the ImageMagick converter "convert" to create the corresponding EPS file
OutputPPM { start = 15 } { convert -colors 256 ppm:- t.eps } {
min = 0 max = 0.4 v = T
}

# Outputs profiling information at the end of the simulation to standard error
OutputTiming { start = end } stderr

}
GfsBox {
# Left boundary on the leftmost box is:
#   Dirichlet U=1 for the x-component of the velocity
left = Boundary {
BcDirichlet U 1
}
}
GfsBox {}
GfsBox {}
GfsBox {}
GfsBox {}
GfsBox {}
GfsBox {}
# Right boundary on the rightmost box is outflow
GfsBox { right = BoundaryOutflow }