function plot_faces(ng,vF,k,ccB);
% plot_faces(ng,vF,k [,ccB]);
%
% make 1 figure (fig. number = ng) composed of Nface parts
% corresponding to level k (enter k=0 if 2D field) of the structured
% array "vF": vF.f001 = face 1, vF.f002 = face 2 ...
% with color range ccB(1),ccB(2) (default = ccB=[0 0] = no call to caxis)

if nargin < 4, ccB=[0 0]; end

%- extract list of faces:
%  convention: faces identificator is "f{n}" (face number n written with 3 digits)
listV=fieldnames(vF); listF=[];
for i=1:size(listV,1)
 cvar=char(listV(i));
 if length(cvar) == 4 & strncmpi('f00',cvar,3),
  if isempty(listF), listF=cvar; else listF=char(listF,cvar); end
 end
end
listF=cellstr(listF);
Nfaces=size(listF,1);
if Nfaces > 6,
  error([' Nb of faces =',int2str(Nfaces),' > 6 !'])
end

xyP=zeros(6,4);
xyP(1,:)=[0.05  0.05  0.20  0.72];
xyP(2,:)=[0.29  0.05  0.20  0.72];
xyP(3,:)=[0.29  0.80  0.20  0.18];
xyP(4,:)=[0.53  0.05  0.20  0.72];
xyP(5,:)=[0.77  0.05  0.20  0.72];
xyP(6,:)=[0.77  0.80  0.20  0.18];

xyP(3,:)=[0.05  0.80  0.20  0.18]; %- move face 3 in top-left corner
figure(ng);clf;
for n=1:Nfaces,
 cvar=char(listF(n)); var=vF.(cvar);
 if k ~= 0, var=var(:,:,k); end
 if n > 3,  var=fliplr(var'); end %- rotate face 4,5,6
 if n == 3, var=flipud(var'); end %- rotate to put face 3 in top-left corner
 AA=axes('position',xyP(n,:));
 imagesc(var'); set(gca,'YDir','normal');
 if ccB(1) < ccB(2), caxis(ccB); end
end
H=colorbar('peer',AA,'North');
set(H,'Position',[xyP(4,1) 0.90 xyP(4,3) 0.020]);

return