mjhjmtu

I am trying to draw a diagram showing the action of soap on grease and dirt. Currently I have the following diagram:

I would like the shapes that surround the large orange-yellow blobs to be the same as the shapes that are free and not bound. The code is as follows:

documentclass[10pt,a4paper]article
usepackage[utf8]inputenc
usepackageamsmath
usepackageamsfonts
usepackageamssymb
usepackagegraphicx
usepackage[left=0.00cm, right=0.00cm]geometry
usepackagetikz
usetikzlibrarycalc,decorations.pathreplacing,fadings
newcommandlipid[3]
 beginscope[xshift=#1cm,yshift=#2cm,rotate=#3]
 shadedraw[shading=radial,inner color=purple!40,outer color=purple!60!black] (0,0) circle (2.5pt);
 shade[shading=linear,top color=purple!60!black,bottom color=green!70!black] (-0.75pt,-2pt) rectangle (0.75pt,-12pt);
 endscope

begindocument
pgfdeclaredecorationlipidleafletinitial

 % Place as many segments as possible along the path to decorate
 % the minimum distance between two segments is set to 7 pt.
 stateinitial[width=pgfdecoratedpathlength/floor(pgfdecoratedpathlength/7pt)]
 
 pgfpathmovetopgfpoint-0.75pt3pt
 pgfpathlinetopgfpoint-0.75pt-7pt
 pgfpathlinetopgfpoint0.75pt-7pt
 pgfpathlinetopgfpoint0.75pt3pt
 % Draw the head group
 pgfpathmovetopgfpoint1pt0pt
 pgfpathcirclepgfpoint0pt5pt2.5pt
 
 statefinal
 
 pgfpathmovetopgfpointdecoratedpathlast
 

begintikzpicture
 % BACKGROUND
 shadedraw[bottom color=cyan!10,top color=cyan!60!blue] (-0.5,0) rectangle (11,7.5);
 draw[thick] (-0.5,0) -- (11,0);
 % LARGE MOLECULES
 shadedraw[shading=radial,inner color=yellow!20,outer color=orange!40] (0,1.5) .. controls (2,1.5) and (3,2) .. (4,2) .. controls (5,2) and (5.5,2) .. (5.5,1.5) .. controls (5.5,1) and (4.5,0.5) .. (4.5,0) -- (-0.5,0) -- (-0.5,1.5) -- cycle;
 shadedraw[shading=radial,inner color=yellow!20,outer color=orange!40] (7,3.5) .. controls (6.5,4) and (7.5,4.5) .. (8,5) .. controls (8.5,5.5) and (9,5.5) .. (9.5,5.5) .. controls (10,5.5) and (10.5,5) .. (10.5,4.5) .. controls (10.5,4) and (10.5,4) .. (10,3.5).. controls (9.5,3) and (9.5,3) .. (8.5,3) .. controls (8,3) and (7.5,3) .. (7,3.5);
 % BOUND LIPIDS
 draw[decorate, decoration=lipidleaflet] (0,1.5) .. controls (2,1.5) and (3,2) .. (4,2) .. controls (5,2) and (5.5,2) .. (5.5,1.5) .. controls (5.5,1) and (4.5,0.5) .. (4.5,0);
 draw[decorate, decoration=lipidleaflet] (7,3.5) .. controls (6.5,4) and (7.5,4.5) .. (8,5) .. controls (8.5,5.5) and (9,5.5) .. (9.5,5.5) .. controls (10,5.5) and (10.5,5) .. (10.5,4.5) .. controls (10.5,4) and (10.5,4) .. (10,3.5).. controls (9.5,3) and (9.5,3) .. (8.5,3) .. controls (8,3) and (7.5,3) .. (7,3.5);
 % FREE LIPIDS
 lipid1620
 lipid5.55.5193
 lipid0.52.5201
 lipid37118
 lipid2.53.5217
 lipid3.55346
 lipid53.526
 lipid6.52.5310
 lipid6.51123
 lipid91353
 % LABELLING
 node at (2,0.5) Grease on Surface;
 node at (9,2.5) Micelle;
 draw (8.7,4.3) -- (7.5,6) node[anchor=south,align=center] Grease particle made\soluble by soap;
endtikzpicture
enddocument

Some of the code comes from http://www.texample.net/tikz/examples/lipid-vesicle/

Ok, I made some refinements:

1. Use pics for the lipids.


2. Adjust their shading angle to make the shading uniform. The shading angle is computed based on the actual orientation of the lipids.


3. Lifted the lipids up. To change the lift, change 2mm in path pic[midway,sloped,yshift=2mm] lipid;
   


4. Cleaned up a bit.

documentclass[10pt,a4paper]article
usepackage[utf8]inputenc
usepackageamsmath
usepackageamsfonts
usepackageamssymb
usepackage[left=0.00cm, right=0.00cm]geometry
usepackagetikz
usetikzlibrarycalc,fadings,decorations.markings

tikzsetpics/.cd,
lipid/.style=code=
shadedraw[shading=radial,inner color=purple!40,outer color=purple!60!black] (0,0) circle (2.5pt);
shade let p1=($(1,0)-(0,0)$),n1=atan2(y1,x1),
p2=($(current bounding box.east)-(current bounding box.west)$),n2=n1-atan2(y2,x2)
 in %pgfextratypeoutn2
 [shading=linear,top color=purple!60!black,bottom color=green!70!black,
shading angle=n2] (-0.75pt,-2pt) rectangle (0.75pt,-12pt);


begindocument
begintikzpicture[multi lipid/.style=decoration=markings,
mark=between positions 0 and 1 step #1 with %
beginscope
path pic[midway,sloped,yshift=2mm] lipid;
endscope
]
 % BACKGROUND
 shadedraw[bottom color=cyan!10,top color=cyan!60!blue] (-0.5,0) rectangle (11,7.5);
 draw[thick] (-0.5,0) -- (11,0);
 % LARGE MOLECULES
 shadedraw[shading=radial,inner color=yellow!20,outer color=orange!40] (0,1.5) .. controls (2,1.5) and (3,2) .. (4,2) .. controls (5,2) and (5.5,2) .. (5.5,1.5) .. controls (5.5,1) and (4.5,0.5) .. (4.5,0) -- (-0.5,0) -- (-0.5,1.5) -- cycle;
 shadedraw[shading=radial,inner color=yellow!20,outer color=orange!40] (7,3.5) .. controls (6.5,4) and (7.5,4.5) .. (8,5) .. controls (8.5,5.5) and (9,5.5) .. (9.5,5.5) .. controls (10,5.5) and (10.5,5) .. (10.5,4.5) .. controls (10.5,4) and (10.5,4) .. (10,3.5).. controls (9.5,3) and (9.5,3) .. (8.5,3) .. controls (8,3) and (7.5,3) .. (7,3.5);
 % BOUND LIPIDS
 draw[decorate,multi lipid=4.2mm] (0,1.5) .. controls (2,1.5) and (3,2) .. (4,2) .. controls (5,2) and (5.5,2) .. (5.5,1.5) .. controls (5.5,1) and (4.5,0.5) .. (4.5,0);
 draw[decorate,multi lipid=4.2mm] (7,3.5) .. controls (6.5,4) and (7.5,4.5) .. (8,5) .. controls (8.5,5.5) and (9,5.5) .. (9.5,5.5) .. controls (10,5.5) and (10.5,5) .. (10.5,4.5) .. controls (10.5,4) and (10.5,4) .. (10,3.5).. controls (9.5,3) and (9.5,3) .. (8.5,3) .. controls (8,3) and (7.5,3) .. (7,3.5);
 % FREE LIPIDS
 path (1,6) pic[rotate=20]lipid
 (5.5,5.5) pic[rotate=193]lipid
 (0.5,2.5) pic[rotate=201]lipid
 (3,7) pic[rotate=118]lipid
 (2.5,3.5) pic[rotate=217]lipid
 (3.5,5) pic[rotate=346]lipid
 (5,3.5) pic[rotate=26]lipid
 (6.5,2.5) pic[rotate=310]lipid
 (6.5,1) pic[rotate=123]lipid
 (9,1) pic[rotate=353]lipid;
 % LABELLING
 node at (2,0.5) Grease on Surface;
 node at (9,2.5) Micelle;
 draw (8.7,4.3) -- (7.5,6) node[anchor=south,align=center] Grease particle made\soluble by soap;
endtikzpicture
enddocument