Changing colours in \foreach loop

Question

I used the following code, from the answer to this question

\documentclass{beamer}
\beamertemplatenavigationsymbolsempty
\usepackage{tikz}
\begin{document}
\begin{frame}[t]
\frametitle{Spirograph 1--}
\begin{tikzpicture}[pics/fcross/.style={code={
\path[fill=blue!40!white, looseness=1,pic actions] 
(0,0) node {x} (0,-2) foreach \X in {0,90,180,270}
{[rotate=\X] -- (0,-2) to [out=0,in=-120] ++ (0.2,0.1) to [out=60,in=-150] ++ (1.7,1.7) to [out=30,in=-90] ++ (0.1,0.2)} -- cycle;
}}]
 \begin{scope}[blend group=lighten,fill opacity=.4]
  \path foreach \Y in {0,30,60} {pic[rotate=\Y,scale=2,line width=.2cm,draw=blue] {fcross}};
 \end{scope} 
\end{tikzpicture}
\end{frame}
\begin{frame}[t]
\frametitle{Spirograph 1}
\begin{tikzpicture}[pics/fcross/.style={code={
\path[line width=.1cm,fill=blue!40!white, looseness=1,pic actions] 
(0,-2) foreach \X in {0,90,180,270}
{[rotate=\X] -- (0,-2) to [out=0,in=-120] ++ (0.2,0.1) to [out=60,in=-150] ++ (1.7,1.7) to [out=30,in=-90] ++ (0.1,0.2)} -- cycle;
}}]
 \begin{scope}[blend group=lighten,fill opacity=.4]
  \path foreach \Y in {0,30,60} {pic[rotate=\Y,scale=2] {fcross}};
 \end{scope} 
 \path foreach \Y in {0,30,60} {pic[rotate=\Y,scale=2,fill=none,draw=blue!40] {fcross}};
\end{tikzpicture}
\end{frame}
\end{document}

How can I make the colour of the filling of the repeated drawings gradient, or produce the following drawings

Answer 1

The previous questions of yours in this context could be answered using an appropriate blend group. Here I think this is no longer the case. Rather, one can use clip. And the different colors can be built in the loop, as mentioned by Colo. Here are examples. The whole story now comes a bit reminiscent of the experimental venndiagrams library, but of course clip has been used all over.

\documentclass{beamer}
\beamertemplatenavigationsymbolsempty
\usepackage{tikz}
\tikzset{contour/.style={insert path={(0,-2) foreach \X in {0,90,180,270}
{[rotate=\X] -- (0,-2) to [out=0,in=-120] ++ (0.2,0.1) to [out=60,in=-150] ++ (1.7,1.7) to [out=30,in=-90] ++ (0.1,0.2)} -- cycle
}}}
\begin{document}
\begin{frame}[t]
\frametitle{Spirograph 1}
\begin{tikzpicture}
\begin{scope}[local bounding box=L]
  \foreach \Y [count=\Z starting from 0]
  in {red,blue,blue!50} 
  {\draw[fill=\Y,rotate=\Z*30,contour,fill opacity=0.5]; }
  \foreach \Y in {0,1,2}
  {\begin{scope}
   \foreach \Z  in {0,1,2}
   {\ifnum\Y=\Z
   \else
    \path[clip,rotate=\Z*30,contour];
   \fi}
   \fill[yellow] (L.south west) rectangle (L.north east);
  \end{scope}}
  \foreach \Z  in {0,1,2}
  {\draw[draw=blue!40,line width=0.5mm,rotate=\Z*30,contour]; }
\end{scope}  
\begin{scope}[local bounding box=R,xshift=5cm]
  \foreach \Y [count=\Z starting from 0]
  in {red,blue,blue!50} 
  {\draw[fill=\Y,draw=blue!40,line width=0.5mm,rotate=\Z*30,contour,fill opacity=0.5]; }
  \foreach \Y in {0,1,2}
  {\begin{scope}
   \foreach \Z  in {0,1,2}
   {\ifnum\Y=\Z
   \else
    \path[clip,rotate=\Z*30,contour];
   \fi}
   \fill[cyan!40] (R.south west) rectangle (R.north east);
  \end{scope}}
\end{scope}  
\end{tikzpicture}
\end{frame}
\end{document}

Answer 2

A metapost solution. Rounded corners were the biggest issue.

\documentclass{article}
\usepackage{luamplib}
\begin{document}
\mplibnumbersystem{double}
\mplibforcehmode
\begin{mplibcode}
u:=1cm; r:=.2cm;
path p[]; pen mypen; color c[];
c1=.7[red,white];
c2=.7[blue,white];
c3=.4[red,white];
c4=(.99,.93,0);
% envelope needs a polygonal pen, so approximate a circular pen
p[-1]:= (r,0) for i=1 upto 120: --(r,0) rotated 3i endfor--cycle;
mypen:= makepen(p[-1]);
pickup mypen;
% set coords so that outer edge of pen hits them, not center
rt z0=u*(2,0);
top z1=u*(0,2);
lft z2=u*(-2,0);
bot z3=u*(0,-2);
p0=z0{dir 150}..{dir 120}z1{dir 240}..{dir 210}z2{dir 330}..{dir 300}z3{dir 60}..{dir 30}z0..cycle;
% draw path with pen of radius=rounded corner radius, envelope=outer boundary of this path
p1=envelope mypen of p0;
% remainder is fairly self explanatory.
p2=p1 rotated 30;
p3=p2 rotated 30;
z4=p1 intersectiontimes p2;
z5=p1 intersectiontimes p3;
p4=subpath (xpart z4-eps,xpart z5+eps) of p1;
p5=subpath (ypart z5-eps,ypart z4+eps) of p3;
p6=subpath (ypart z4-eps,length p2+xpart z4+eps) of p2;
p7=buildcycle(p4,p5,p6);

beginfig(0);
for i=1 upto 3: fill p[i] withcolor c4; endfor;
for i=0 upto 3:
    for j=0 upto 3:
        fill p7 rotated (30i+90j) withcolor c[i];
    endfor;
endfor;
for i=1 upto 3: draw p[i] withcolor .5[blue,white]; endfor;
endfig;

beginfig(1);
for i=1 upto 3: fill p[i] withcolor .8[blue,white]; endfor;
for i=0 upto 3:
    for j=0 upto 3:
        fill p7 rotated (30i+90j) withcolor c[i];
        draw p7 rotated (30i+90j) withcolor .5[blue,white];
    endfor;
endfor;
endfig;
\end{mplibcode}
\end{document}