Steps of generating the graph, not evident from the command, are:
1) Define upper limit (avoid spikes drawing):
	set `--upper-limit = AVERAGE(median)*1.5`;
2) From 1 до Х (ping count in Smokeping RRD) add:
      `DEF:pingX=/var/lib/smokeping/r1_lab_local.rrd:pingX:AVERAGE`
3) Round up `packet loss` - will later be compared to integer:
      CDEF:loss_rnd=loss,CEIL
4) For each packet loss level, from 1 to Y, create 2 variables, lossY_1 и lossY_2, drawn on even and odd intervals on the graph (to avoid vertical lines between 2 intervals with same packet loss level):
      CDEF:lossY=loss_rnd,Y,EQ,median,UNKN,IF
      CDEF:lossY_1=COUNT,2,%,0,EQ,lossY,UNKN,IF
      CDEF:lossY_2=COUNT,2,%,1,EQ,lossY,UNKN,IF 
  as result we have lossY line which exists only when packet loss is at level Y (e.g. 1 of 20 packets)
5) For each pingX calculate smokeX by subtracting median from pingX:
      CDEF:smokeX=pingX,median,-
6) For each smokeX draw a 20% transparent black area above/below the transparent median:
      LINE2:median#E300FC00:"2/20"
      AREA:smokeX#00000020:"SmokeX":STACK 
7) Draw median on top of the smoke, colored according to the packet loss level:
      LINE2:lossY_1#E300FC:"2/20"
      LINE2:lossY_2#E300FC:"2/20"
   colors can be defined with $config['smokeping']['color']['1']='E300FC' .. $config['smokeping']['color']['Y']='221100'
	
That's it. Maybe, not optimal, but working. I'm always ready to answer any questions about this implementation.