HistogramFill := proc (X::list,R::range,m::posint) 
local YYY, YY, Y, n, l, u, v, i, j, k, p, t, U, V, count, 
   truemin, truemax, nint, pnts, pnts1, jj, P1, P2; 
option `July 7, 1993 -- Zaven A. Karian`; 
description `Graphic display of histogram`; 
YY := sort(evalf(args[1])); 
n := nops(YY); 
if nargs = 1 then truemin := YY[1]; 
truemax := YY[n]; 
nint := 8 else 
truemin := lhs(args[2]); 
truemax := rhs(args[2]); 
nint := args[3] fi; 
count := 0; 
for i to n do 
if YY[i] < truemin or truemax < YY[i] then count := count+1 fi od; 
if 0 < count then print(`WARNING: There are`,count,` data points out of plot range.`) fi; 
j := 1; 
YYY := array(1 .. n); 
u := array(1 .. nint+1); 
v := array(1 .. nint+1); 
for i to n do 
if truemin <= YY[i] and YY[i] <= truemax then YYY[j] := YY[i]; 
j := j+1 
fi 
od; 
n := j-1; 
Y := [seq(YYY[k],k = 1 .. n)]; 
p := array(1 .. 8*nint); 
l := (truemax-truemin)/nint; 
u[1] := truemin; 
v[1] := 0; 
for i from 2 to nint+1 do 
u[i] := u[i-1]+l; 
v[i] := 0 od; 
if u[nint+1] < Y[n] then u[nint+1] := Y[n] fi; 
i := 2; for j to n do 
if Y[j] <= u[i] then v[i-1] := v[i-1]+1 else i := i+1; 
j := j-1 fi od; 
t := 1; 
for i to nint do 
U[t] := u[i]; 
V[t] := 0; 
t := t+1; 
U[t] := U[t-1]; 
V[t] := v[i]; 
t := t+1; 
U[t] := U[t-1]+l; 
V[t] := v[i]; 
t := t+1; 
U[t] := U[t-1]; 
V[t] := 0; 
t := t+1 
od; 
for i to t-1 do 
p[2*i-1] := U[i]; 
p[2*i] := V[i]/(l*n) 
od; 
pnts := [seq([p[2*i-1], p[2*i]],i = 1 .. t-1)];
pnts1 := [seq([[pnts[4*(jj-1)+1], pnts[4*(jj-1)+2],pnts[4*(jj-1)+3], 
         pnts[4*(jj-1)+4]]], jj = 1 .. nint)]: 
P1 := plots[polygonplot](pnts1,color=wheat):
P2 := plot(pnts,color = black,linestyle = 1, thickness=2):
display({P1,P2});
end: