Here's my improved version of Kitonum's ContoursWithLabels. Now there's no specific variable name dependence, and I've added separate keyword options to control each plot.

Download ContoursWithLabels.mw

plots:-polygonplot3d([A1, A2, A3]);

Here's an easier way for your whole code:

block:= ListTools:-Reverse~(Bits:-Split~(convert(message, bytes), bits= 8)):
Block:= Matrix(block):
Block[..,3..7]:= 1 -~ Block[..,3..7]:
cblock:= convert(Block, listlist);

Depending on what your next operation is, it may be better to skip the last command and just keep it in Matrix form.

Here's a variant that uses the special ways that Matrices can be indexed:

SelectRealRows:= (M::Matrix)-> M[remove(i-> has(M[i,..], I), [$1..op([1,1],M)]), ..];

The reason is that filled is an option to the plot command, not an option to the PLOT data structure. In other words, plot does some computation to construct the polygon to fill; it's not the plot renderer that does it.

Here's a workaround. This should work for any 2D plot with a single curve. (But, mind you, this is quick-and-dirty; I only tested it on DensityPlots.)

FillPlot:= proc(P::specfunc(PLOT))
local
     C:= indets(P, specfunc(CURVES))[1],
     A:= convert(op(1,C), listlist)
;
     PLOT(
          POLYGONS(
               [[A[1][1],0], A[], [A[-1][1],0], [A[1,1],0]],
               LEGEND("__never_display_this_legend_entry"),
               STYLE(PATCHNOGRID),
               TRANSPARENCY(0.4),
               indets(C, specfunc(COLOUR))[]
          ),
          op(P)
     )
end proc:    

FillPlot(DensityPlot(X));       

To retain the symbolic constants, use solve instead of fsolve.

There is a way to create true symbolic constants, but you can't get fsolve to express solutions in terms of them; fsolve is strictly numeric.

Two ways. In the first, change g to

g:= proc(t)
local j;
     if not t::numeric then return 'procname'(t) end if;
    ... the rest of g ...

And change the plot command to

plot([g(t)[1], g(t)[2], t= 0..1]);

The second way is to simplify everything:

f0:= t-> (t, 3.9*t*(1-t)):
IFS:= (i,x,y)-> piecewise(i=0, [y,x], i=1, [x,y+1], i=2, [x,y]+~1, i=3, [2-y,1-x])[]/2:
g:= t-> IFS(trunc(4*t), f0(frac(4*t))):
plot([g(t)[1], g(t)[2], t= 0..1]);

Why have you put m3 in square brackets? That's the problem.

Also with*matrix and with*linearalgebra don't mean anything. Get rid of those.

Try changing Do(HD= HuffmanCoding(HT)) to
Do(HD= [HuffmanCoding(HT)]).

The reason is that I doubt that Do can handle the assignment of an expression sequence with more than one term, which is what the output of HuffmanCoding will be.

Here's an example:

Download DataFrame_string_filter.mw

However, it's a disappointment that the commands select, remove, and selectremove haven't been overloaded to work with DataSeries and DataFrames.

Here's an easy example that you should be able to execute on your own computer.

I'm nearly certain at this point, so I'll make this an Answer:

I think that the last statement of OrderB is of the form print(x). You need to change that to either return(x), return x, or simply x. It doesn't matter which one. A procedure should never use print to return its final value. The purpose of print is to display supplementary information on the screen.

The differential equations and the initial conditions need to be in a single set. So, you need to

dsolve(IVP union ICs, numeric);

Delta:= D[2,1,1] + D[2,1] + D[2,3,3] + D[1,1] + D[3,1,1]:

To use it:

Delta(f)(x,y,z);

Here's a workaround.

Download cosh_integral.mw

Obviously the result is true for negative k also.