ProbHistFill := proc () 
local n, L, LL, lp, ap, A, MIN, dim, i,j, k, p, var, Min, Max, pnts1,pnts2,pnts, P1, P2, xtics; 
option `January 26, 1994 -- Zaven A. Karian, November 29, 1999, E. Tanis`; 
description `Graphic display of probability histogram`; 
if nargs = 1 and not type(args[1],list) 
  then ERROR(`If one argument is used, it must be a probability   list`) fi; 
if nargs = 2 and not type(args[1],algebraic) then ERROR(`If two arguments are used, the first must be an expression`) fi; 
if nargs = 2 and not type(args[2],range) then ERROR(`If two arguments are used, the second must be a range`) fi; 
if nargs = 1 then n := nops(args[1]); 
L := copy(args[1]); 
A := array(1 .. 4*n); 
lp := 1; 
ap := 1; 
for i to 1/2*n do 
  A[ap] := L[lp]-1/2; 
  A[ap+1] := 0; 
  A[ap+2] := A[ap]; 
  A[ap+3] := L[lp+1]; 
  A[ap+4] := L[lp]+1/2; 
  A[ap+5] := L[lp+1]; 
  A[ap+6] := A[ap+4]; 
  A[ap+7] := 0;
  LL[i] := [seq([A[ap + 2*j-2],A[ap + 2*j-1]],j=1..4)];
  #LL[i] := [seq([A[ap+2*j-2], A[ap+2*j-1]], j=1..4)]: 
  lp := lp+2; 
  ap := ap+8; 
 od; 
 pnts2 := [seq([A[2*j-1], A[2*j]],j = 1 .. 2*n)]:
  pnts1 := [seq(LL[j], j = 1 .. n/2)]:
P1 := plots[polygonplot](pnts1,color=wheat):
xtics := [seq(k, k = 0 .. L[1]),seq(L[2*j+1], j = 0 .. n/2-1)]:
#xtics := [seq(L[1] + j-1, j = L[1] .. ((L[n-1]-L[1])/2+1))]:  
P2 := PLOT(CURVES(pnts2), AXESTICKS(xtics,[0.05=`0.05`,0.1=`0.10`, 0.15=`0.15`, 0.2=`0.20`, 0.25=`0.25`, 0.3=`0.30`, 0.3=`0.35`])):
display({P1,P2}): 
 else Min := lhs(args[2]); 
  Max := rhs(args[2]); 
  dim := 8*trunc(Max-Min+1/1000000000)+8; 
  A := array(1 .. dim); 
  MIN := Min; 
  var := op(select(type,indets(args[1]),name));
  n := Max - Min + 1: 
for i to n do 
  p := evalf(subs(var = MIN,args[1])); 
  A[8*i-7] := MIN-1/2; 
  A[8*i-6] := 0; 
  A[8*i-5] := MIN-1/2; 
  A[8*i-4] := p; 
  A[8*i-3] := MIN+1/2; 
  A[8*i-2] := p; 
  A[8*i-1] := MIN+1/2; 
  A[8*i] := 0;
  LL[i] := [seq([A[8*i-(8-2*j+1)],A[8*i-(8-2*j)]],j=1..4)];
  MIN := MIN+1 
od;
pnts1 := [seq(LL[i], i = 1 .. n)]: 
pnts2 := [seq([A[2*i-1], A[2*i]],i = 1 .. 4*Max-4*Min+4)]; 
# plot(%,color = blue);
P1 := plots[polygonplot](pnts1,color=wheat):
xtics := [seq(Min + k-1, k = 1 .. (Max - Min+1))]:  
P2 := PLOT(CURVES(pnts2), AXESTICKS(xtics,[0.05=`0.05`,0.1=`0.10`, 0.15=`0.15`, 0.2=`0.20`, 0.25=`0.25`, 0.3=`0.30`, 0.3=`0.35`])):
display({P1, P2}); 
fi 
end: