Starting work on multi-drop to see influence on bleaching.

Meshes/multi_drop.geo

+lc = 0.3;
+Point(1) = {0, 0, 0, lc};
+Point(2) = {4, 0,  0, lc};
+Point(3) = {4, 4, 0, lc};
+Point(4) = {0,  4, 0, lc};
+
+di = 1;
+Point(5)={1+di,1+di,0.5,0.1};
+Point(6)={1.5+di,1.5+di,0.5,0.1};
+Point(7)={0.5+di,0.5+di,0.5,0.1};
+Point(8)={1+di,1.5+di,0.5,0.1};
+Point(9)={1.5+di,1+di,0.5,0.1};
+Point(10)={1+di,0.5+di,0.5,0.1};
+Point(11)={0.5+di,1+di,0.5,0.1};
+Point(12)={1.5+di, 0.5+di, 0.5,0.1};
+Point(13)={0.5+di,1.5+di,0.5,0.1};
+
+Line(1) = {1,2};
+Line(2) = {3,2};
+Line(3) = {3,4};
+Line(4) = {4,1};
+Curve Loop(1) = {4,1,-2,3};
+Plane Surface(1) = {1};
+Physical Curve(5) = {1, 2, 4};
+Physical Surface("My surface") = {1};
+Extrude {0, 0, 4} { Surface{1}; }
+Field[1] = Distance;
+Field[1].NodesList = {5,6,7,8,9,10,11,12,13};
+Field[1].NNodesByEdge = 100;
+Field[2] = Threshold;
+Field[2].IField = 1;
+Field[2].LcMin = lc / 20;
+Field[2].LcMax = lc;
+Field[2].DistMin = 0.5;
+Field[2].DistMax = 0.6;
+Field[3] = Min;
+Field[3].FieldsList = {2};
+Background Field = 3;
+Physical Volume("Volume", 1) = {1};